Meningococcal vaccines (MenACWY, MenB, MenC, MenA conjugate)

← All vaccines

disease risks

post-acute and long-term sequelae

vaccine efficacy and effectiveness

vaccine safety and adverse events

sources

Invasive meningococcal disease (meningitis and septicaemia) Neisseria meningitidis (serogroups A, B, C, W, X, Y)

Disease risks

Acute risks of the infection itself: complications, hospitalisation, ICU, death.

Outcome (O)	Population (P)	Estimate	Design (S)	Source
Death from invasive meningococcal disease (pooled national case-fatality rate) severity: death case definition: National surveillance CFRs of IMD, 40 studies, 163,758 patients	all ages vaccination status: not reported country: multiple (national surveillance studies, mostly high-income) period: studies published 2000-2018 n: 163,758 IMD patients All ages	8.3 (7.5–9.1) CFR (%) per IMD case	meta-analysis 40 studies	Wang et al. 2019 Vaccine quote CFRs ranged from 4.1% to 20.0% with the pooled overall CFR of 8.3% (95% confidence interval (CI): 7.5-9.1%). abstract, RESULTS Random-effects pooled CFR across heterogeneous national systems (range 4.1-20.0%). Serogroup-specific CFRs from the same review are separate records.
Death from serogroup B invasive meningococcal disease severity: death strain: serogroup B case definition: National surveillance CFRs by serogroup	all ages vaccination status: not reported country: multiple period: studies published 2000-2018 All ages	6.9 (6.0–7.8) CFR (%) per serogroup B IMD case	meta-analysis	Wang et al. 2019 Vaccine quote Serogroup B was associated with a lower pooled CFR (6.9% (95%CI: 6.0-7.8%)) than other serogroups (W: 12.8% (95%CI: 10.7-15.0%); C: 12.0% (95%CI: 10.5-13.5%); Y: 10.8% (95%CI: 8.2-13.4%)). abstract, RESULTS Lower than serogroups C, W and Y in the same meta-analysis.
Death from serogroup W invasive meningococcal disease severity: death strain: serogroup W case definition: National surveillance CFRs by serogroup	all ages vaccination status: not reported country: multiple period: studies published 2000-2018 All ages	12.8 (10.7–15.0) CFR (%) per serogroup W IMD case	meta-analysis	Wang et al. 2019 Vaccine quote Serogroup B was associated with a lower pooled CFR (6.9% (95%CI: 6.0-7.8%)) than other serogroups (W: 12.8% (95%CI: 10.7-15.0%); C: 12.0% (95%CI: 10.5-13.5%); Y: 10.8% (95%CI: 8.2-13.4%)). abstract, RESULTS Highest serogroup-specific pooled CFR in the review.
Death from serogroup C invasive meningococcal disease severity: death strain: serogroup C case definition: National surveillance CFRs by serogroup	all ages vaccination status: not reported country: multiple period: studies published 2000-2018 All ages	12.0 (10.5–13.5) CFR (%) per serogroup C IMD case	meta-analysis	Wang et al. 2019 Vaccine quote Serogroup B was associated with a lower pooled CFR (6.9% (95%CI: 6.0-7.8%)) than other serogroups (W: 12.8% (95%CI: 10.7-15.0%); C: 12.0% (95%CI: 10.5-13.5%); Y: 10.8% (95%CI: 8.2-13.4%)). abstract, RESULTS
Death from serogroup Y invasive meningococcal disease severity: death strain: serogroup Y case definition: National surveillance CFRs by serogroup	all ages vaccination status: not reported country: multiple period: studies published 2000-2018 All ages	10.8 (8.2–13.4) CFR (%) per serogroup Y IMD case	meta-analysis	Wang et al. 2019 Vaccine quote Serogroup B was associated with a lower pooled CFR (6.9% (95%CI: 6.0-7.8%)) than other serogroups (W: 12.8% (95%CI: 10.7-15.0%); C: 12.0% (95%CI: 10.5-13.5%); Y: 10.8% (95%CI: 8.2-13.4%)). abstract, RESULTS
Death from laboratory-confirmed IMD, modelled CFR by age severity: death case definition: Laboratory-confirmed IMD cases in national surveillance; mixed-effects logistic regression with cubic spline on age	infants (<1 year), with the curve falling to 7-year-olds and rising to 28-year-olds and older adults vaccination status: not reported country: multiple period: studies published 2000-2018 Infant <1y	9.0 CFR (%), model-predicted per laboratory-confirmed IMD case	meta-analysis	Wang et al. 2019 Vaccine quote For laboratory confirmed IMD cases, the predicted CFR was 9.0% in infants, gradually decreased to 7.0% in 7-year olds, subsequently increased to 15.0% in young adults aged 28 years, stabilised between 15 and 20% in mid-aged adults and reached a high in elderly people. abstract, RESULTS Same sentence gives 7.0% at age 7, 15.0% at age 28 and 15-20% in middle-aged adults; modelled, not observed, values.
Death from invasive meningococcal disease, range across national systems severity: death case definition: National surveillance CFRs	all ages vaccination status: not reported country: multiple period: studies published 2000-2018 All ages	4.1 to 20.0 CFR (%), range across 40 studies per IMD case	systematic review	Wang et al. 2019 Vaccine quote CFRs ranged from 4.1% to 20.0% with the pooled overall CFR of 8.3% (95% confidence interval (CI): 7.5-9.1%). abstract, RESULTS The spread between countries and eras; the pooled value is the first burden record.
Early death from invasive meningococcal disease severity: death within 48 hours case definition: IMD (septicaemia and/or meningitis)	all ages vaccination status: not reported country: high-income countries period: literature 2001-2016 All ages	5 to 10 proportion of patients dying within 48 h (%) per IMD patient	systematic review	Olbrich et al. 2018 Infect Dis Ther quote INTRODUCTION: Invasive meningococcal disease (IMD, septicaemia and/or meningitis) has a severe acute and long-term burden: 5-10% of patients die within 48 h, and long-term sequelae have been reported in 10-20% of survivors. abstract, INTRODUCTION Background statement of a GSK-funded sequelae review, not a pooled estimate.
Death from invasive meningococcal disease severity: death case definition: Invasive, reportable meningococcal disease	all ages vaccination status: mixed country: United States period: current (Pink Book, 2021 edition) All ages	10 to 15 CFR (%) per IMD case	expert body	cdc.gov quote The overall case-fatality ratio of meningococcal disease is 10% to 15%, even with appropriate antibiotic therapy, and can be higher in persons with meningococcemia. Clinical Features section Expert-body summary figure; the same sentence says CFR can be higher with meningococcaemia. Sequelae figure from the same passage is a separate post-acute record.
Death from invasive meningococcal disease severity: death case definition: Meningococcal disease with appropriate antimicrobial therapy	all ages vaccination status: mixed country: United States period: ACIP summary, 2020 All ages	15 CFR (%) per IMD case	expert body	cdc.gov quote Even with appropriate antimicrobial therapy, the overall case-fatality ratio in the United States is 15%, and 10%–20% of survivors have long-term sequelae such as neurologic disability, limb or digit loss, or hearing loss ( 22 , 23 ). Background, Meningococcal Disease Same sentence gives 10-20% of survivors with long-term sequelae (post-acute record).
Death from serogroup W invasive meningococcal disease severity: death strain: serogroup W (ST-11 clonal complex predominant) case definition: Confirmed MenW IMD, enhanced national surveillance with GP follow-up	all ages vaccination status: mixed country: England period: 2011-2017 n: 877 cases with clinical data All ages	12.7 CFR (%) per MenW IMD case	cohort	Isitt et al. 2026 J Infect quote MenW IMD case fatality rate (CFR) was 12.7% (110/877) overall, but significantly higher for the 2013 strain (15.0%, 51/340) than for the original UK strain (9.8%, 30/305) for the 2013 strain and for other MenW strains (7.2%, 6/83) (p=0.05). abstract, RESULTS Same sentence gives higher CFR for the later-emerging strain than for the original UK strain and other MenW strains. Older age and septicaemic presentation independently predicted death.
Death during a serogroup C meningococcal meningitis epidemic (home follow-up) severity: death strain: serogroup C case definition: Notified cases traced at home months after the epidemic	all ages vaccination status: not reported country: Niger setting: meningitis belt epidemic, LMIC period: 2022 n: 570 cases found All ages	8.6 CFR (%) per traced case	cohort	Idrissa et al. 2025 PLoS One quote Of these 570 cases, 49 had died (CFR 8.6%). abstract, RESULTS
Invasive meningococcal disease incidence, all serogroups severity: any invasive disease case definition: Cases reported to the National Notifiable Diseases Surveillance System	all ages vaccination status: mixed country: United States setting: national surveillance period: 2006-2015 (post-MenACWY adolescent recommendation) n: 7924 cases All ages	0.26 incidence per 100,000 population per year per population	surveillance	MacNeil et al. 2018 Clin Infect Dis quote RESULTS: During the years 2006-2015, 7924 cases of meningococcal disease were reported to NNDSS, resulting in an average annual incidence of 0.26 cases per 100000 population; 14.9% of cases were fatal. abstract, RESULTS Same sentence gives the case-fatality ratio (separate record). Period follows the MenACWY adolescent recommendation; most cases are serogroup B, Y or C.
Death from invasive meningococcal disease severity: death case definition: Cases reported to NNDSS	all ages vaccination status: mixed country: United States setting: national surveillance period: 2006-2015 n: 7924 cases All ages	14.9 CFR (%) per reported IMD case	surveillance	MacNeil et al. 2018 Clin Infect Dis quote RESULTS: During the years 2006-2015, 7924 cases of meningococcal disease were reported to NNDSS, resulting in an average annual incidence of 0.26 cases per 100000 population; 14.9% of cases were fatal. abstract, RESULTS
Serogroup distribution of IMD cases (serogroup B share) severity: any invasive disease strain: serogroup B case definition: Cases with serogroup information reported to NNDSS	all ages vaccination status: mixed country: United States period: 2006-2015 All ages	35.8 proportion of cases (%) per IMD case with serogroup information	surveillance	MacNeil et al. 2018 Clin Infect Dis quote Among cases with serogroup information, 2290 (35.8%) were serogroup B, 1827 (28.5%) were serogroup Y, 1457 (22.8%) were serogroup C, 436 (6.8%) were serogroup W, and 392 (6.1%) were other serogroups. abstract, RESULTS Same sentence: Y 28.5%, C 22.8%, W 6.8%, other 6.1%.
Invasive meningococcal disease incidence, all serogroups, pre-MenACWY period severity: any invasive disease case definition: Confirmed and probable N. meningitidis cases reported to NNDSS	all ages (national) vaccination status: unvaccinated country: United States setting: national surveillance period: 2000-2005 (before MenACWY introduction) All ages	0.61 incidence per 100,000 population per year per population	surveillance	Mbaeyi et al. 2020 JAMA Pediatr quote RESULTS: The national incidence of meningococcal disease declined from 0.61 cases per 100 000 population during the prevaccine period (2000-2005) to 0.15 cases per 100 000 population during the post-booster dose period (2011-2017). abstract, RESULTS Same sentence gives the post-booster-period rate (next record). Incidence was already declining before the vaccine, so the fall is not all attributable to vaccination.
Invasive meningococcal disease incidence, all serogroups, post-booster period severity: any invasive disease case definition: Confirmed and probable N. meningitidis cases reported to NNDSS	all ages (national) vaccination status: mixed country: United States setting: national surveillance period: 2011-2017 (after MenACWY booster recommendation) All ages	0.15 incidence per 100,000 population per year per population	surveillance	Mbaeyi et al. 2020 JAMA Pediatr quote RESULTS: The national incidence of meningococcal disease declined from 0.61 cases per 100 000 population during the prevaccine period (2000-2005) to 0.15 cases per 100 000 population during the post-booster dose period (2011-2017). abstract, RESULTS
Invasive meningococcal disease incidence in infants severity: any invasive disease case definition: Culture-confirmed meningococcal disease, Active Bacterial Core surveillance	infants younger than 1 year vaccination status: unvaccinated country: United States setting: active population-based surveillance period: 2006-2012 n: estimated 113 cases per year Infant <1y	2.74 incidence per 100,000 infants per year per infant population	surveillance	MacNeil et al. 2015 Pediatrics quote RESULTS: An estimated 113 cases of culture-confirmed meningococcal disease occurred annually among infants aged <1 year in the United States from 2006 through 2012, for an overall incidence of 2.74 per 100,000 infants. abstract, RESULTS Infants are not routinely offered meningococcal vaccine in the US. Serogroup B caused most infant cases (next record).
Serogroup B share of infant IMD cases severity: any invasive disease strain: serogroup B case definition: Culture-confirmed infant meningococcal disease, ABCs	infants younger than 1 year vaccination status: unvaccinated country: United States period: 2006-2012 Infant <1y	64 proportion of cases (%) per infant IMD case	surveillance	MacNeil et al. 2015 Pediatrics quote Serogroup B was responsible for 64%, serogroup C for 12%, and serogroup Y for 16% of infant cases. abstract, RESULTS Same sentence: serogroup C 12%, serogroup Y 16%.
Invasive meningococcal disease incidence severity: any invasive disease case definition: Reported invasive meningococcal disease cases	all ages vaccination status: mixed country: United States period: 2018 n: 329 cases All ages	0.10 incidence per 100,000 population per population	surveillance	cdc.gov quote In 2018, 329 total cases were reported in the United States, representing an incidence of 0.10 per 100,000 population. Secular Trends in the United States Historic low; the CDC surveillance page cached separately reports cases rising again after the pandemic (next record).
Invasive meningococcal disease cases, preliminary count severity: any invasive disease case definition: Confirmed and probable cases reported to CDC	all ages vaccination status: mixed country: United States period: 2025 (preliminary) All ages	463 number of cases (count, not a rate) per population (national count)	surveillance	cdc.gov quote People disproportionately affected by this increase include: People between the ages of 30 and 60 years Black or African American people Adults with HIV For Health Care Providers Clinical Guidance for Meningococcal Disease In 2025, 463 confirmed and probable cases were reported based on preliminary data. Key points Preliminary data; the page states cases have increased sharply since the pandemic and exceed pre-pandemic levels, concentrated in middle-aged adults, Black or African American people and adults with HIV. A count, not an incidence rate.
Serogroup C invasive meningococcal disease incidence before MenC conjugate vaccine severity: any invasive disease strain: serogroup C case definition: Laboratory-confirmed MenC cases, national surveillance	all ages vaccination status: unvaccinated country: England period: 1998/99 (year before MenC conjugate introduction) n: 883 cases All ages	1.81 incidence per 100,000 population per population	surveillance	Findlow et al. 2019 Euro Surveill quote We compared bactericidal antibody assay results using anonymised sera from 2014 to similar data from 1996-1999, 2000-2004 and 2009.ResultsMenC cases fell from 883 in 1998/99 (1.81/100,000 population) to 42 cases (0.08/100,000 population) in 2015/16. abstract, Results Same sentence gives the much lower rate after many years of the MenC programme (next record).
Serogroup C invasive meningococcal disease incidence after MenC conjugate programme severity: any invasive disease strain: serogroup C case definition: Laboratory-confirmed MenC cases, national surveillance	all ages vaccination status: mixed country: England period: 2015/16 n: 42 cases All ages	0.08 incidence per 100,000 population per population	surveillance	Findlow et al. 2019 Euro Surveill quote We compared bactericidal antibody assay results using anonymised sera from 2014 to similar data from 1996-1999, 2000-2004 and 2009.ResultsMenC cases fell from 883 in 1998/99 (1.81/100,000 population) to 42 cases (0.08/100,000 population) in 2015/16. abstract, Results Reflects direct and herd protection from the MenC/MenACWY programmes.
Invasive meningococcal disease notification rate, all serogroups severity: any invasive disease case definition: IMD cases notified to EU/EEA surveillance	all ages vaccination status: mixed country: EU/EEA countries setting: national surveillance period: 2004-2014 All ages	0.9 notification rate per 100,000 population per year per population	surveillance	Whittaker et al. 2017 Vaccine quote RESULTS: The overall NR was 0.9/100 000 population, and decreased 6.6% (95%CI: -8.0%;-5.1%) annually. abstract, RESULTS Decreasing 6.6% annually over the period.
Invasive meningococcal disease notification rate in infants severity: any invasive disease case definition: IMD cases notified to EU/EEA surveillance	infants (<1 year) vaccination status: mixed country: EU/EEA countries period: 2004-2014 Infant <1y	16.0 notification rate per 100,000 population per year per infant population	surveillance	Whittaker et al. 2017 Vaccine quote Infants had the highest NR (16.0/100 000), and there were decreasing trends in all age groups <50years. abstract, RESULTS Mostly before any MenB infant programme (the UK programme started in September of the final year).
Serogroup B share of IMD cases severity: any invasive disease strain: serogroup B case definition: IMD cases notified to EU/EEA surveillance with serogroup	all ages vaccination status: mixed country: EU/EEA countries period: 2004-2014 All ages	74 proportion of cases (%) per IMD case	surveillance	Whittaker et al. 2017 Vaccine quote Serogroup B (SgB) caused 74% of all cases, and the majority of cases in all age groups. abstract, RESULTS
Suspected meningitis cases and deaths before serogroup A conjugate vaccine severity: death case definition: Suspected meningitis (clinical case definition, all causes) in national surveillance	all ages vaccination status: unvaccinated country: Burkina Faso setting: meningitis belt, LMIC period: 14 years before PsA-TT (MenAfriVac) introduction, 1997-2010 All ages	17 965 number of deaths (count over 14 years) per population (national count, suspected meningitis of all causes)	surveillance	Novak et al. 2012 Lancet Infect Dis quote FINDINGS: During the 14 year period before PsA-TT introduction, Burkina Faso had 148 603 cases of suspected meningitis with 17 965 deaths, and 174 district-level epidemics. abstract, FINDINGS A 14-year total of suspected, not confirmed, meningitis; 174 district-level epidemics in the same period. Not a rate and not serogroup-specific.
Epidemic meningitis cases and deaths, serogroup A clone III-1 pandemic wave severity: death strain: serogroup A (subgroup III) case definition: Reported meningitis cases during the 1994-95 epidemic season (strains isolated all A:4:P1.9/clone III-1)	all ages vaccination status: not reported country: Niger setting: meningitis belt epidemic, LMIC period: November 1994 to April 1995 n: 23814 reported cases All ages	2227 number of deaths (count) per reported meningitis case (23814)	surveillance	Riou et al. 1996 Bull World Health Organ quote All were A:4:P1.9/clone III-1; between November 1994 and April 1995 there were 23814 cases of meningitis reported of which 2227 resulted in death. abstract Pre-conjugate era epidemic; counts only, CFR not computed here.
Death during a serogroup C meningococcal meningitis epidemic (routine surveillance) severity: death strain: serogroup C (87% of confirmed cases) case definition: Suspected meningitis cases notified during the 2022 epidemic, two districts	all ages vaccination status: not reported country: Niger setting: meningitis belt epidemic, LMIC period: 2022 n: 1001 suspected cases All ages	5.0 CFR (%) per suspected case	surveillance	Idrissa et al. 2025 PLoS One quote RESULTS: A total of 1001 suspected cases and 50 deaths (CFR 5.0%) were reported in the two districts. abstract, RESULTS Home follow-up of the same cases found a higher CFR (next record); routine surveillance under-ascertained deaths.
Invasive meningococcal disease incidence before MenC vaccine severity: any invasive disease case definition: Notified invasive meningococcal disease (60% group B, 30% group C)	all ages vaccination status: unvaccinated country: Ireland period: 1999 (pre-MenC vaccine) All ages	14.75 incidence per 100,000 population per population	surveillance	Ó et al. 2016 Arch Dis Child quote BACKGROUND: In 1999, invasive meningococcal disease was hyperendemic in Ireland at 14.75/100 000 population, with 60% group B and 30% group C diseases. abstract, BACKGROUND Pre-vaccine peak year in a hyperendemic country; the same paper notes a spontaneous decline in group B afterwards.
In-hospital death from invasive meningococcal disease severity: death case definition: Laboratory-confirmed IMD at 26 sentinel hospitals (GERMS-SA)	all ages vaccination status: unvaccinated country: South Africa setting: sentinel hospitals, LMIC, negligible vaccine use period: 2003-2016 n: 1479 cases with outcome All ages	17 CFR (%) per IMD case with known outcome	surveillance	Meiring et al. 2019 Clin Infect Dis quote The in-hospital case-fatality rate was 17% (247/1479). abstract, RESULTS About a third of tested cases were HIV-coinfected; serogroup W was about half of typed cases.
Invasive meningococcal disease incidence in HIV-infected versus HIV-uninfected people severity: any invasive disease case definition: Laboratory-confirmed IMD, national surveillance	all ages immune status: HIV-infected vaccination status: unvaccinated country: South Africa period: 2012-2016 All ages	2.5 (2.2–2.8) age-adjusted relative risk ratio (HIV-infected vs uninfected) per population	surveillance	Meiring et al. 2019 Clin Infect Dis quote The IMD incidence in HIV-infected persons was higher for all age categories, with an age-adjusted relative risk ratio (aRRR) of 2.5 (95% confidence interval [CI] 2.2-2.8; P < .001) from 2012-2016. abstract, RESULTS Risk-group record; HIV coinfection was twice as common with serogroup W and Y disease.
Serogroup B meningococcal disease in college students versus non-students severity: any invasive disease strain: serogroup B case definition: NNDSS and enhanced surveillance cases aged 18-24	18 to 24 years risk group: college students vaccination status: mixed country: United States period: 2014-2016 18-49y	3.54 (2.21–5.41) relative risk (college vs non-college students) per population	surveillance	Mbaeyi et al. 2019 Pediatrics quote The RR of serogroup B meningococcal (MenB) disease in college students versus noncollege students was 3.54 (95% confidence interval: 2.21-5.41), and the RR of serogroups C, W, and Y combined was 0.56 (95% confidence interval: 0.27-1.14). abstract, RESULTS Same sentence: RR for serogroups C, W and Y combined was 0.56 (0.27-1.14), i.e. no excess for the MenACWY-covered serogroups in students.
Invasive meningococcal disease incidence in young adults severity: any invasive disease case definition: Meningococcal disease cases in persons aged 18-24	18 to 24 years vaccination status: mixed country: United States period: 2014-2016 n: 166 cases 18-49y	0.17 incidence per 100,000 population per year per population	surveillance	Mbaeyi et al. 2019 Pediatrics quote RESULTS: From 2014 to 2016, 166 cases of meningococcal disease occurred in persons aged 18 to 24 years, with an average annual incidence of 0.17 cases per 100 000 population. abstract, RESULTS
Death from serogroup C meningococcal disease during an urban epidemic severity: death strain: serogroup C case definition: Laboratory-confirmed serogroup C IMD, population-based surveillance	under 5 and 10-24 years (campaign target groups) vaccination status: unvaccinated country: Brazil setting: citywide epidemic, Salvador, LMIC period: 2010 n: 51 confirmed cases Infant <1y1-4y5-11y12-17y18-49y	25 CFR (%) per confirmed MenC case	surveillance	Cardoso et al. 2015 PLoS One quote Overall case-fatality was 25%. abstract, METHODS AND FINDINGS Epidemic setting with a small case count; none of the cases had been vaccinated.
Confirmed non-serogroup A meningococcal meningitis after MenAfriVac campaigns severity: any confirmed disease strain: non-A serogroups (C, W, X) case definition: Laboratory-confirmed non-A meningococcal cases, WHO IST surveillance, nine countries	all ages vaccination status: vaccinated country: Benin, Burkina Faso, Chad, Cote d'Ivoire, Ghana, Mali, Niger, Nigeria, Togo setting: meningitis belt, LMIC period: 2005-2015 All ages	2.76 (1.21–6.30) incidence rate ratio (post- vs pre-campaign, non-A serogroups) per population	surveillance	Trotter et al. 2017 Lancet Infect Dis quote The IRR for non-A serogroups was higher after completion of MenAfriVac campaigns (IRR 2·76, 95% CI 1·21-6·30). abstract, FINDINGS Possible serogroup replacement or secular emergence of C/W/X after the serogroup A vaccine; the authors call for continued surveillance. Not a vaccine effect on A disease.
Death among children hospitalised with invasive meningococcal disease severity: death strain: serogroup B predominant (94%) case definition: Meningococcal cases at two tertiary paediatric hospitals (94% group B)	children under 19 years, median 5 years vaccination status: mixed country: Ireland setting: tertiary paediatric hospitals period: 2001-2011 n: 382 cases Infant <1y1-4y5-11y12-17y	3.6 CFR (%) per hospitalised paediatric IMD case	case series	Ó et al. 2016 Arch Dis Child quote Fifteen patients (3.6%) died. abstract, RESULTS Tertiary-centre series; most needed PICU (next record). Lower than national CFRs because deaths before hospital arrival are missed.
PICU admission among children with invasive meningococcal disease severity: ICU admission case definition: Meningococcal cases at two tertiary paediatric hospitals	children under 19 years, median 5 years vaccination status: mixed country: Ireland setting: tertiary paediatric hospitals period: 2001-2011 n: 382 cases Infant <1y1-4y5-11y12-17y	61 proportion of cases admitted to PICU (%) per hospitalised paediatric IMD case	case series	Ó et al. 2016 Arch Dis Child quote 221 (61%) were admitted to paediatric intensive care units (PICU). abstract, RESULTS
Invasive meningococcal disease risk in patients receiving eculizumab severity: any invasive disease case definition: Meningococcal disease in terminal complement inhibitor recipients	eculizumab recipients (adults and children) risk group: terminal complement inhibitor (eculizumab) treatment immune status: complement-inhibited vaccination status: vaccinated country: United States period: 2008-2016 All ages	1,000 to 2,000 fold increase in incidence vs general population per population	case series	McNamara et al. 2017 MMWR Morb Mortal Wkly Rep quote Use of eculizumab (Soliris, Alexion Pharmaceuticals), a terminal complement inhibitor, is associated with a 1,000-fold to 2,000-fold increased incidence of meningococcal disease (1). abstract Most US cases had received at least one dose of meningococcal vaccine before onset and most were nongroupable strains not covered by any vaccine. Vaccination does not remove this risk.

Vaccine efficacy and effectiveness

Every estimate compiled, annotated by population (P), intervention (I), comparator (C), outcome (O) and study design (S).

Outcome (O)	Population (P)	Intervention / comparator	Estimate	Design (S)	Source
Serogroup C invasive meningococcal disease severity: any invasive disease strain: serogroup C case definition: Effectiveness studies from 9 countries with routine MCCV programmes	all programme ages country: UK, Spain, Italy, Canada, Brazil, Australia, Belgium, Germany, Netherlands period: studies 2001-2017 Infant <1y1-4y5-11y12-17y	monovalent MenC conjugate (MCCV) platform: polysaccharide-protein conjugate doses: programme-dependent vs unvaccinated (mostly screening method)	38 to 100 VE (%), range across 17 effectiveness studies	systematic review	Tin et al. 2020 BMC Public Health quote Vaccine effectiveness (VE) was mostly assessed through screening methods and ranged from 38 to 100%. abstract, RESULTS No pooled estimate; VE was highest in the first year and waned, and was better maintained where catch-up campaigns in older children and adolescents were used.
Serogroup A meningococcal meningitis severity: any meningitis strain: serogroup A case definition: Serogroup A meningitis in randomised trials (8 included after excluding 4 at high risk of bias)	mostly over 5 years (also Finnish children 3 months-5 years and Nigerian/Sudanese 1-5-year-olds) country: multiple (Finland, Nigeria, Sudan and others) period: trials from the 1970s-1980s 1-4y5-11y12-17y18-49y	serogroup A plain POLYSACCHARIDE vaccine (not conjugate) platform: unconjugated polysaccharide doses: 1 time since vaccination: first year after vaccination vs placebo or control vaccine	95 (87–99) VE (%) within the first year	meta-analysis	Patel et al. 2005 Cochrane Database Syst Rev quote MAIN RESULTS: The protective effect within the first year of vaccination was consistent across the randomised trials, and the summary vaccine efficacy was 95% (95% confidence interval (CI) 87% to 99%). abstract, MAIN RESULTS Historical polysaccharide vaccine, not MenAfriVac. Protection beyond the first year did not reach statistical significance; efficacy in children under 5 could not be determined precisely.
Oropharyngeal carriage of disease-causing meningococci (groups A, B, C, W, X, Y) severity: carriage (not disease) strain: disease-causing genogroups, including B case definition: PCR-detected carriage at 12 months in year 10-11 students, cluster-randomised by school	15 to 18 years country: Australia (South Australia) period: 2017-2018 n: 24,269 students, 237 schools 12-17y18-49y	4CMenB (Bexsero) platform: multicomponent recombinant protein plus OMV doses: 2 time since vaccination: 12 months vs unvaccinated control schools (vaccinated at 12 months)	1.02 (0.80–1.31) adjusted OR for carriage, vaccinated vs control schools	cluster RCT	Marshall et al. 2020 N Engl J Med quote At 12 months, there was no difference in the prevalence of carriage of disease-causing N. meningitidis between the vaccination group (2.55%; 326 of 12,746) and the control group (2.52%; 291 of 11,523) (adjusted odds ratio, 1.02; 95% confidence interval [CI], 0.80 to 1.31; P = 0.85). abstract, RESULTS Null result: 2.55% vs 2.52% carriage. 4CMenB does not reduce carriage, so no herd protection is expected from adolescent MenB programmes, unlike MenC/MenACWY conjugates.
Serum bactericidal antibody (hSBA) titre at or above LLOQ against 4 heterologous MenB test strains, 48 months after primary series (IMMUNOGENICITY SURROGATE, not disease) severity: surrogate (no clinical outcome) strain: serogroup B (4 test strains) case definition: hSBA >= 1:8 or 1:16 against four FHbp-heterologous MenB strains	11 to 18 years at primary vaccination country: Czech Republic, Denmark, Germany, Sweden period: 2012-2015 n: 465 subjects in persistence stage 12-17y	MenB-FHbp (Trumenba, bivalent rLP2086) platform: recombinant lipidated factor H binding protein doses: 2 or 3 time since vaccination: 48 months vs same subjects 1 month after primary series (73.8-100.0% >= LLOQ)	18.0 to 61.3 proportion of subjects with hSBA >= LLOQ at 48 months (%), range across 5 schedule groups	RCT	Vesikari et al. 2019 Vaccine quote Response rates declined during the 12 months after last primary vaccination and then remained stable through 48 months, with 18.0-61.3% of subjects depending on study group having hSBA titers ≥LLOQ at this time point. abstract, FINDINGS Immunogenicity only; MenB-FHbp has no clinical efficacy or effectiveness estimate. Responses fell over the first year then plateaued; a booster at four years restored nearly all subjects to at or above LLOQ. Pfizer-funded open-label extension.
Oropharyngeal carriage of serogroup C meningococci severity: carriage (not disease) strain: serogroup C case definition: Carriage surveys of 48,309 samples during and after MCC introduction, isolates genotyped	under 19 years (programme-eligible, mostly adolescents in the carriage surveys) country: United Kingdom period: 1999-2001 n: 48,309 swabs 5-11y12-17y	MenC conjugate (MCC) platform: polysaccharide-protein conjugate doses: 1 (catch-up) vs unvaccinated carriage prevalence	75 VE against carriage (%)	cohort	Maiden et al. 2008 J Infect Dis quote Vaccine efficacy against carriage was 75%, and vaccination had a disproportionate impact on the carriage of sequence type (ST)-11 complex serogroup C meningococci that (rate ratio, 0.06); these meningococci also exhibited high rates of capsule expression. abstract, RESULTS Serogroup C carriage fell about five-fold with no serogroup replacement; the basis of the herd effect that protected unvaccinated infants.
Laboratory-confirmed serogroup C meningococcal disease severity: any invasive disease strain: serogroup C case definition: Confirmed MenC cases during the 2010 Salvador epidemic, matched to neighbourhood controls	under 5 years and 10-24 years country: Brazil setting: citywide epidemic mass campaign, LMIC period: 2010 n: 50 cases, 240 controls Infant <1y1-4y5-11y12-17y18-49y	MenC conjugate vaccines (campaign) platform: polysaccharide-protein conjugate doses: at least 1 vs unvaccinated matched controls	98 (89–) VE (%)	case-control	Cardoso et al. 2015 PLoS One quote Overall effectiveness of MenC was 98% with a lower 95% exact confidence limit of 89%. abstract, METHODS AND FINDINGS Only the lower 95% exact confidence limit (89%) is reported; no vaccinated cases.
Serogroup A, C, W or Y meningococcal disease severity: any invasive disease strain: serogroups A, C, W, Y combined case definition: Culture- or PCR-confirmed serogroup A/C/W/Y disease in adolescents, US surveillance sites	adolescents country: United States period: 2006-2013 12-17y18-49y	MenACWY-D (Menactra) platform: polysaccharide-diphtheria toxoid conjugate doses: 1 time since vaccination: 0 to 8 years vs unvaccinated friend and school controls	69 (51–80) VE (%)	case-control	Cohn et al. 2017 Pediatrics quote The overall VE estimate 0 to 8 years postvaccination was 69% (51% to 80%); VE was 79% (49% to 91%) at <1 year, 69% (44% to 83%) at 1 to <3 years, and 61% (25% to 79%) at 3 to <8 years. abstract, RESULTS Adjusted for underlying conditions and smoking. Waning by time since vaccination and serogroup-specific VE are separate records; these estimates led ACIP to add an adolescent booster.
Serogroup A, C, W or Y meningococcal disease severity: any invasive disease strain: serogroups A, C, W, Y combined case definition: Confirmed A/C/W/Y disease in adolescents	adolescents country: United States period: 2006-2013 12-17y18-49y	MenACWY-D (Menactra) platform: polysaccharide-diphtheria toxoid conjugate doses: 1 time since vaccination: less than 1 year vs unvaccinated friend and school controls	79 (49–91) VE (%) less than 1 year after vaccination	case-control	Cohn et al. 2017 Pediatrics quote The overall VE estimate 0 to 8 years postvaccination was 69% (51% to 80%); VE was 79% (49% to 91%) at <1 year, 69% (44% to 83%) at 1 to <3 years, and 61% (25% to 79%) at 3 to <8 years. abstract, RESULTS Same sentence: 69% (44-83) at 1 to <3 years and 61% (25-79) at 3 to <8 years.
Serogroup A, C, W or Y meningococcal disease severity: any invasive disease strain: serogroups A, C, W, Y combined case definition: Confirmed A/C/W/Y disease in adolescents	adolescents and young adults country: United States period: 2006-2013 12-17y18-49y	MenACWY-D (Menactra) platform: polysaccharide-diphtheria toxoid conjugate doses: 1 time since vaccination: 3 to less than 8 years vs unvaccinated friend and school controls	61 (25–79) VE (%) 3 to <8 years after vaccination	case-control	Cohn et al. 2017 Pediatrics quote The overall VE estimate 0 to 8 years postvaccination was 69% (51% to 80%); VE was 79% (49% to 91%) at <1 year, 69% (44% to 83%) at 1 to <3 years, and 61% (25% to 79%) at 3 to <8 years. abstract, RESULTS Waning from 79% in the first year.
Serogroup C meningococcal disease severity: any invasive disease strain: serogroup C case definition: Confirmed serogroup C disease in adolescents	adolescents country: United States period: 2006-2013 12-17y18-49y	MenACWY-D (Menactra) platform: polysaccharide-diphtheria toxoid conjugate doses: 1 time since vaccination: 0 to 8 years vs unvaccinated friend and school controls	77 (57–88) VE (%)	case-control	Cohn et al. 2017 Pediatrics quote VE was 77% (57% to 88%) against serogroup C and 51% (1% to 76%) against serogroup Y. abstract, RESULTS Same sentence: 51% (1-76) against serogroup Y (next record).
Serogroup Y meningococcal disease severity: any invasive disease strain: serogroup Y case definition: Confirmed serogroup Y disease in adolescents	adolescents country: United States period: 2006-2013 12-17y18-49y	MenACWY-D (Menactra) platform: polysaccharide-diphtheria toxoid conjugate doses: 1 time since vaccination: 0 to 8 years vs unvaccinated friend and school controls	51 (1–76) VE (%)	case-control	Cohn et al. 2017 Pediatrics quote VE was 77% (57% to 88%) against serogroup C and 51% (1% to 76%) against serogroup Y. abstract, RESULTS Lower and less precise than against serogroup C; interval almost reaches zero.
Oropharyngeal carriage of genogroup C, W or Y meningococci severity: carriage (not disease) strain: genogroups C, W, Y combined case definition: Culture-defined carriage in two cross-sectional school surveys before (2014-15) and after (2018) MenACWY programme	15 to 19 years country: United Kingdom period: 2014-2018 n: 10,625 pre- and 13,438 post-implementation 12-17y18-49y	MenACWY conjugate (UK adolescent programme, 84% coverage) platform: polysaccharide-protein conjugate doses: 1 vs pre-programme carriage prevalence	0.34 (0.27–0.44) OR for carriage, post- vs pre-programme	cohort	Carr et al. 2022 Clin Microbiol Infect quote Carriage of genogroups C, W, and Y (combined) decreased from 2.03 to 0.71% (OR 0.34 [95% CI 0.27-0.44], p < 0.001). abstract, RESULTS Genogroup B carriage did not change, supporting a specific effect rather than secular change. Basis for herd protection.
Invasive meningococcal disease caused by any serogroup severity: any invasive disease strain: all serogroups case definition: Laboratory-confirmed IMD in children under 60 months, nationwide matched case-control	under 60 months country: Spain setting: private-purchase vaccine (not a public programme) period: October 2015 to October 2019 n: 306 cases, 1224 controls Infant <1y1-4y	4CMenB (Bexsero) platform: multicomponent recombinant protein plus OMV doses: 2 or more per manufacturer schedule (complete) vs unvaccinated matched controls (date of birth and province)	76 (57–87) VE (%)	case-control	Castilla et al. 2023 N Engl J Med quote The effectiveness of complete vaccination with 4CMenB (defined as receipt of at least 2 doses, administered in accordance with the manufacturer's recommendations) was 76% (95% confidence interval [CI], 57 to 87) against invasive meningococcal disease caused by any serogroup, and partial vaccination was 54% (95% CI, 18 to 74) effective. abstract, RESULTS Partial vaccination 54% (18-74). Private purchase means vaccinated children likely differ socioeconomically from controls; matching on province only partly addresses this.
Serogroup B invasive meningococcal disease severity: any invasive disease strain: serogroup B case definition: Laboratory-confirmed MenB IMD in children under 60 months	under 60 months country: Spain period: October 2015 to October 2019 Infant <1y1-4y	4CMenB (Bexsero) platform: multicomponent recombinant protein plus OMV doses: 2 or more (complete) vs unvaccinated matched controls	71 (45–85) VE (%)	case-control	Castilla et al. 2023 N Engl J Med quote Complete vaccination resulted in an effectiveness of 71% (95% CI, 45 to 85) against meningococcal serogroup B disease. abstract, RESULTS None of the case patients with genetically vaccine-covered strains had been vaccinated.
Non-serogroup B invasive meningococcal disease (cross-protection) severity: any invasive disease strain: non-B serogroups case definition: Laboratory-confirmed non-B IMD in children under 60 months	under 60 months country: Spain period: October 2015 to October 2019 Infant <1y1-4y	4CMenB (Bexsero) platform: multicomponent recombinant protein plus OMV doses: at least 1 vs unvaccinated matched controls	82 (21–96) VE (%)	case-control	Castilla et al. 2023 N Engl J Med quote Vaccine effectiveness with at least one dose of 4CMenB was 64% (95% CI, 41 to 78) against serogroup B disease and 82% (95% CI, 21 to 96) against non-serogroup B disease. abstract, RESULTS Same sentence: 64% (41-78) against serogroup B with at least one dose.
Serogroup B invasive meningococcal disease severity: any invasive disease strain: serogroup B case definition: Serogroup B IMD in children under 6 years, matched case-control in 6 regions	under 6 years, fully immunised country: Italy (6 regions) period: 2006-2020 n: 26 cases, 52 controls Infant <1y1-4y5-11y	4CMenB (Bexsero) platform: multicomponent recombinant protein plus OMV doses: full schedule vs unvaccinated matched controls	95.6 (71.7–99.1) VE (%)	case-control	Lodi et al. 2023 JAMA Netw Open quote The case-control method involving 6 highly-populated Italian regions included 26 cases and 52 controls and found an estimated VE of 92.4% (95% CI, 67.6%-97.9%) in children old enough for the first vaccine dose and 95.6% (95% CI, 71.7%-99.1%) in fully immunized children. abstract, RESULTS A slightly lower estimate applies to children old enough for at least the first dose. A sizeable share of unvaccinated cases were infants too young for the first dose.
Serogroup B invasive meningococcal disease severity: any invasive disease strain: serogroup B (single predominant clone) case definition: Regional mass vaccination of persons aged 2 months-20 years in a Canadian region with a single predominant clone	2 months to 20 years country: Canada (Saguenay-Lac-Saint-Jean, Quebec) period: 4 years after campaign Infant <1y1-4y5-11y12-17y18-49y	MenB-4C (4CMenB, Bexsero) platform: multicomponent recombinant protein plus OMV doses: per age schedule time since vaccination: up to 4 years vs unvaccinated	79 (-231–99) VE (%)	cohort	cdc.gov quote Effectiveness of MenB Vaccines After a mass vaccination program among persons aged 2 months–20 years in a region of Canada experiencing increased incidence of serogroup B meningococcal disease due predominantly to a single clone, MenB-4C vaccine effectiveness among all target age groups was estimated at 79% (95% CI: −231% to 99%) in the 4 years postvaccination, although the wide confidence intervals encompassing the null effect value limit the interpretation of the finding ( 235 ). MenB vaccines, Effectiveness section ACIP itself notes the wide interval encompassing the null limits interpretation.
Gonorrhoea (off-target cross-protection, Neisseria gonorrhoeae) severity: any infection strain: N. gonorrhoeae (not meningococcus) case definition: Notified gonorrhoea, case-control with age-matched chlamydia cases as controls	adolescents and young adults (15-20 years at programme start) country: Australia (South Australia) period: 2019-2020 12-17y18-49y	4CMenB (Bexsero) platform: multicomponent recombinant protein plus OMV doses: 2 vs chlamydia-infected controls (to balance sexual-risk behaviour)	32.7 (8.3–50.6) VE (%)	case-control	Wang et al. 2022 Lancet Infect Dis quote Estimated two-dose vaccine effectiveness against gonorrhoea in adolescents and young adults was 32·7% (8·3-50·6) based on the case-control method using age-matched individuals with chlamydia infection as controls. abstract, FINDINGS Off-target outcome included because it bears on the vaccine's overall value; waning after three years and after five years is reported in the later follow-ups.
Oropharyngeal carriage of serogroup A meningococci severity: carriage (not disease) strain: serogroup A case definition: Repeated cross-sectional carriage surveys in 3 districts, 25,521 swabs	1 to 29 years country: Burkina Faso setting: meningitis belt, LMIC period: 2009-2011 n: 25,521 oropharyngeal samples 1-4y5-11y12-17y18-49y	MenAfriVac (PsA-TT) platform: serogroup A polysaccharide-tetanus toxoid conjugate doses: 1 time since vaccination: 3 weeks to 13 months vs pre-vaccination baseline carriage	0.39 baseline NmA carriage prevalence (%) before vaccination; none identified after vaccination	cohort	Kristiansen et al. 2013 Clin Infect Dis quote Compared with a baseline NmA carriage prevalence of 0.39%, no NmA was identified after vaccination. abstract, RESULTS Carriage eliminated in both vaccinated and unvaccinated people, consistent with herd immunity.
Oropharyngeal carriage of serogroup A meningococci 7 years after MenAfriVac severity: carriage (not disease) strain: serogroup A case definition: Four cross-sectional carriage surveys in two districts, whole-genome sequenced isolates	9 months to 36 years country: Burkina Faso setting: meningitis belt, LMIC period: 2016-2017 n: 13,758 participants Infant <1y1-4y5-11y12-17y18-49y	MenAfriVac (PsA-TT), 2010 campaign plus routine introduction platform: serogroup A polysaccharide-tetanus toxoid conjugate doses: 1 time since vaccination: about 7 years vs pre-campaign carriage (2009)	0 serogroup A carriage prevalence (%)	cohort	Mbaeyi et al. 2020 Lancet Infect Dis quote Accounting for the complex survey design, prevalence of meningococcal carriage was 7·60% (95% CI 5·67-9·52), including 6·98% (4·86-9·11) non-groupable, 0·48% (0·01-0·95) serogroup W, 0·10% (0·01-0·18) serogroup C, 0·03% (0·00-0·80) serogroup E, and 0% serogroup A. abstract, FINDINGS Overall carriage 7.60% (mostly non-groupable), serogroup W 0.48%, C 0.10%; the serogroup A effect persisted across vaccinated and unvaccinated cohorts.
Serogroup C invasive meningococcal disease severity: any invasive disease strain: serogroup C case definition: Confirmed MenC disease, enhanced national surveillance	teenagers (catch-up campaign) country: England period: first 9 months after introduction, 1999-2000 12-17y	MenC conjugate (MCC) platform: polysaccharide-protein conjugate doses: 1 time since vaccination: 0-9 months vs unvaccinated (screening method)	97 (77–99) VE (%)	screening method	Ramsay et al. 2001 Lancet quote Increased surveillance during the first 9 months since introduction has shown that short-term efficacy of the MCC vaccine in England was 97% (95% CI 77-99) for teenagers and 92% (65-98) for toddlers. abstract Licensed on immunogenicity without an efficacy trial; this is the first post-licensure estimate. Same sentence gives 92% (65-98) for toddlers (next record).
Serogroup C invasive meningococcal disease severity: any invasive disease strain: serogroup C case definition: Confirmed MenC disease, enhanced national surveillance	toddlers country: England period: first 9 months after introduction, 1999-2000 1-4y	MenC conjugate (MCC) platform: polysaccharide-protein conjugate doses: 1 time since vaccination: 0-9 months vs unvaccinated (screening method)	92 (65–98) VE (%)	screening method	Ramsay et al. 2001 Lancet quote Increased surveillance during the first 9 months since introduction has shown that short-term efficacy of the MCC vaccine in England was 97% (95% CI 77-99) for teenagers and 92% (65-98) for toddlers. abstract
Serogroup C invasive meningococcal disease severity: any invasive disease strain: serogroup C case definition: Confirmed MenC disease, national surveillance to June 2009	infants vaccinated with a 3-dose course in infancy country: England and Wales period: 1999-2009 Infant <1y	MenC conjugate (MCC) platform: polysaccharide-protein conjugate doses: 3 schedule: 3-dose infant course (2, 3, 4 months) time since vaccination: less than 1 year vs unvaccinated (screening method)	97 (91–99) VE (%)	screening method	Campbell et al. 2010 Clin Vaccine Immunol quote Updated estimates of vaccine effectiveness through 30 June 2009 confirmed high short-term protection after vaccination in infancy, at 97% (95% confidence interval [CI], 91% to 99%), falling to 68% (95% CI, -63% to 90%) more than a year after vaccination. abstract Same sentence gives the much lower, imprecise VE more than a year after vaccination (next record): protection in infants waned within a year, which drove the move to a second-year booster.
Serogroup C invasive meningococcal disease severity: any invasive disease strain: serogroup C case definition: Confirmed MenC disease, national surveillance to June 2009	infants vaccinated with a 3-dose course in infancy country: England and Wales period: 1999-2009 Infant <1y1-4y	MenC conjugate (MCC) platform: polysaccharide-protein conjugate doses: 3 schedule: 3-dose infant course without booster time since vaccination: more than 1 year vs unvaccinated (screening method)	68 (-63–90) VE (%)	screening method	Campbell et al. 2010 Clin Vaccine Immunol quote Updated estimates of vaccine effectiveness through 30 June 2009 confirmed high short-term protection after vaccination in infancy, at 97% (95% confidence interval [CI], 91% to 99%), falling to 68% (95% CI, -63% to 90%) more than a year after vaccination. abstract Interval includes zero; waning after infant priming without a booster. Despite this, MenC disease stayed at record lows because of herd protection from the catch-up campaign.
Serogroup C invasive meningococcal disease severity: any invasive disease strain: serogroup C case definition: Laboratory-confirmed MenC cases, national surveillance	vaccinated at 5-18 years (catch-up campaign) country: England period: 1998/99-2015/16 5-11y12-17y	MenC conjugate (MCC) platform: polysaccharide-protein conjugate doses: 1 time since vaccination: 8 or more years vs unvaccinated (screening method)	95.0 (76.0–99.5) VE (%) at 8 or more years after vaccination	screening method	Findlow et al. 2019 Euro Surveill quote After vaccination at 5-18 years, high VE was sustained for ≥ 8 years; 95.0% (95% CI: 76.0- 99.5%). abstract, Results The same abstract reports significantly lower VE over time after infant immunisation and after a single dose at ages one to four, without numbers. Age at vaccination determines durability.
Serogroup C invasive meningococcal disease severity: any invasive disease strain: serogroup C case definition: Confirmed MenC cases notified to the Spanish surveillance system	all vaccine-targeted cohorts (routine infants and catch-up to adolescence) country: Spain period: 2001-2013 Infant <1y1-4y5-11y12-17y	MenC conjugate platform: polysaccharide-protein conjugate doses: 1 to 3 depending on programme vs unvaccinated (screening method)	94.83 (93.37–95.97) VE (%), overall	screening method	Garrido-Estepa et al. 2014 Vaccine quote Overall VE was 94.83 (CI95%: 93.37, 95.97), 98.82 (CI95%: 97.96, 99.31) and 90.89 (CI95%: 87.79, 93.21) for ≤ 1 and >1 year since vaccination, respectively. abstract, RESULTS Same sentence gives 98.82 (97.96-99.31) within 1 year and 90.89 (87.79-93.21) beyond 1 year since vaccination (next records).
Serogroup C invasive meningococcal disease severity: any invasive disease strain: serogroup C case definition: Confirmed MenC cases, Spanish surveillance	all vaccine-targeted cohorts country: Spain period: 2001-2013 Infant <1y1-4y5-11y12-17y	MenC conjugate platform: polysaccharide-protein conjugate doses: 1 to 3 depending on programme time since vaccination: 1 year or less vs unvaccinated (screening method)	98.82 (97.96–99.31) VE (%) within 1 year of vaccination	screening method	Garrido-Estepa et al. 2014 Vaccine quote Overall VE was 94.83 (CI95%: 93.37, 95.97), 98.82 (CI95%: 97.96, 99.31) and 90.89 (CI95%: 87.79, 93.21) for ≤ 1 and >1 year since vaccination, respectively. abstract, RESULTS
Serogroup C invasive meningococcal disease severity: any invasive disease strain: serogroup C case definition: Confirmed MenC cases, Spanish surveillance	all vaccine-targeted cohorts country: Spain period: 2001-2013 Infant <1y1-4y5-11y12-17y	MenC conjugate platform: polysaccharide-protein conjugate doses: 1 to 3 depending on programme time since vaccination: more than 1 year vs unvaccinated (screening method)	90.89 (87.79–93.21) VE (%) more than 1 year after vaccination	screening method	Garrido-Estepa et al. 2014 Vaccine quote Overall VE was 94.83 (CI95%: 93.37, 95.97), 98.82 (CI95%: 97.96, 99.31) and 90.89 (CI95%: 87.79, 93.21) for ≤ 1 and >1 year since vaccination, respectively. abstract, RESULTS Overall waning is modest because catch-up cohorts vaccinated at older ages dominate; infant-only cohorts wane much more (next record).
Serogroup C invasive meningococcal disease severity: any invasive disease strain: serogroup C case definition: Confirmed MenC cases in vaccine-targeted cohorts, Spanish surveillance, modelled against time since vaccination	vaccinated before 1 year of age country: Spain period: 2001-2013 Infant <1y1-4y5-11y12-17y	MenC conjugate platform: polysaccharide-protein conjugate doses: 2 or 3 infant doses (schedule varied over the period) time since vaccination: 10 years vs unvaccinated (screening method)	48.60 VE (%) at 10 years since vaccination (modelled)	screening method	Garrido-Estepa et al. 2015 Vaccine quote Using the best model for each group, vaccine effectiveness decreased from 99.12% to 90.85% (%change=-8.3%) for all; from 99.04% to 48.60% (%change=-50.9%) for those vaccinated at <1 years and from 99.45% to 90.18% (%change=-9.3%) for those vaccinated at 1-11 years after 10 years since vaccination. abstract, RESULTS Modelled decline from near-complete protection at vaccination; those vaccinated at older childhood ages fell only slightly and those vaccinated as adolescents showed no change over ten years.
Serogroup C, W or Y invasive meningococcal disease severity: any invasive disease strain: serogroups C, W, Y combined case definition: Laboratory-confirmed IMD in adolescents eligible for the emergency MenACWY programme	adolescents aged 13-18 years at vaccination country: England period: 2015-2019 12-17y18-49y	MenACWY conjugate (MenACWY-TT / MenACWY-CRM, UK programme) platform: polysaccharide-protein conjugate doses: 1 vs unvaccinated (indirect screening method)	94 (80–99) VE (%)	screening method	Campbell et al. 2022 Lancet Child Adolesc Health quote Ignoring any residual effect from an earlier MenC-containing vaccine, the overall vaccine effectiveness against MenCWY disease combined was 94% (95% CI 80-99). abstract, FINDINGS Ignores residual protection from the earlier MenC-containing vaccine, so this may overstate the quadrivalent vaccine's own contribution.
Serogroup W invasive meningococcal disease severity: any invasive disease strain: serogroup W case definition: IMD-W cases in the national surveillance system, vaccine-eligible toddlers	15 to 36 months country: Netherlands period: 2018-2020 1-4y	MenACWY-TT (replacing MenC at 14 months) platform: polysaccharide-tetanus toxoid conjugate doses: 1 vs unvaccinated (screening method)	92 (-20–99.5) VE (%)	screening method	Ohm et al. 2022 Clin Infect Dis quote VE was 92% (95% CI, -20 to 99.5) in vaccine-eligible toddlers (aged 15-36 months). abstract, RESULTS Interval includes zero because of few cases. No IMD-W cases occurred in vaccine-eligible teenagers after the campaign, so no VE could be computed for them.
Serogroup B invasive meningococcal disease severity: any invasive disease strain: serogroup B (all strains) case definition: Laboratory-confirmed MenB cases in vaccine-eligible infants, enhanced national surveillance	infants eligible for routine 2- and 4-month doses country: England period: September 2015 to June 2016 Infant <1y	4CMenB (Bexsero) platform: multicomponent recombinant protein plus OMV doses: 2 schedule: 2 and 4 months (reduced priming) time since vaccination: first 10 months of programme vs unvaccinated (screening method)	82.9 (24.1–95.2) VE (%)	screening method	Parikh et al. 2016 Lancet quote Two-dose vaccine effectiveness was 82·9% (95% CI 24·1-95·2) against all MenB cases, equivalent to a vaccine effectiveness of 94·2% against the highest predicted MenB strain coverage of 88%. abstract, FINDINGS Against all MenB strains; equivalent to 94.2% against the predicted vaccine-covered 88% of strains. Wide interval from a short observation window.
Serogroup B invasive meningococcal disease severity: any invasive disease strain: serogroup B case definition: Laboratory-confirmed MenB cases, enhanced national surveillance	infants with 2 priming doses country: England period: September 2015 to August 2018 Infant <1y	4CMenB (Bexsero) platform: multicomponent recombinant protein plus OMV doses: 2 schedule: 2 and 4 months vs unvaccinated (indirect screening method)	52.7 (-33.5–83.2) VE (%)	screening method	Ladhani et al. 2020 N Engl J Med quote The adjusted vaccine effectiveness against meningococcal group B disease was 52.7% (95% CI, -33.5 to 83.2) with a two-dose priming schedule for infants and 59.1% (95% CI, -31.1 to 87.2) with a two-dose priming schedule plus a booster at 1 year). abstract, RESULTS Interval crosses zero. Same sentence gives 59.1% (-31.1 to 87.2) for 2 doses plus the 1-year booster (next record). The screening method is imprecise at very high coverage.
Serogroup B invasive meningococcal disease severity: any invasive disease strain: serogroup B case definition: Laboratory-confirmed MenB cases, enhanced national surveillance	children with 2 priming doses plus 12-month booster country: England period: September 2015 to August 2018 Infant <1y1-4y	4CMenB (Bexsero) platform: multicomponent recombinant protein plus OMV doses: 3 schedule: 2, 4 and 12 months time since vaccination: up to 2 years after booster vs unvaccinated (indirect screening method)	59.1 (-31.1–87.2) VE (%)	screening method	Ladhani et al. 2020 N Engl J Med quote The adjusted vaccine effectiveness against meningococcal group B disease was 52.7% (95% CI, -33.5 to 83.2) with a two-dose priming schedule for infants and 59.1% (95% CI, -31.1 to 87.2) with a two-dose priming schedule plus a booster at 1 year). abstract, RESULTS Interval crosses zero; authors conclude protection after three doses was sustained for at least two years based mainly on the impact analysis (previous records).
Serogroup B invasive meningococcal disease severity: any invasive disease strain: serogroup B case definition: Serogroup B IMD in children under 6 years without predisposing factors, regional surveillance and vaccination registries	under 6 years, fully immunised country: Italy (3 regions) period: 2006-2020 n: resident population 587,561 Infant <1y1-4y5-11y	4CMenB (Bexsero) platform: multicomponent recombinant protein plus OMV doses: full schedule per regional programme vs unvaccinated (screening method)	94.9 (83.1–98.4) VE (%)	screening method	Lodi et al. 2023 JAMA Netw Open quote Analyses found that 4CMenB VE in fully immunized children was 94.9% (95% CI, 83.1%-98.4%) using the screening method and 91.7% (95% CI, 24.4%-98.6%) using the case-control method. abstract, RESULTS Same sentence gives a lower, imprecise case-control estimate. Overall IRR reduction was larger in regions with early-start schedules.
Serogroup B invasive meningococcal disease severity: any invasive disease strain: serogroup B case definition: Notified serogroup B IMD in children targeted by the South Australia programme	infants and children 0-3 years at programme start country: Australia (South Australia) period: October 2018 to 2020 Infant <1y1-4y	4CMenB (Bexsero) platform: multicomponent recombinant protein plus OMV doses: 2 vs unvaccinated (screening method)	94.2 (36.6–99.5) VE (%)	screening method	Wang et al. 2022 Lancet Infect Dis quote Two-dose vaccine effectiveness against serogroup B meningococcal disease was estimated to be 94·2% (95% CI 36·6-99·5) using the screening method and 94·7% (40·3-99·5) using the case-control method in children, and 100% in adolescents and young adults (no cases reported after implementation). abstract, FINDINGS 94.7% (40.3-99.5) by case-control in the same sentence; 100% in adolescents (no cases after implementation, so not estimable). Close antigenic match between vaccine and local strains noted by the authors.
Serogroup B invasive meningococcal disease severity: any invasive disease strain: serogroup B case definition: Notified serogroup B IMD, South Australia programme, 5-year evaluation	children (childhood programme) country: Australia (South Australia) period: 2018-2023 Infant <1y1-4y5-11y	4CMenB (Bexsero) platform: multicomponent recombinant protein plus OMV doses: 3 time since vaccination: up to 5 years vs unvaccinated (screening and case-control methods)	98.5 (81.9–99.9) VE (%)	screening method	Wang et al. 2025 Clin Infect Dis quote VE against MenB disease for the 3-dose schedule was 98.5% (95% CI, 81.9%-99.9%) in children and 92.3% (34.3%-99.1%) for the 2-dose vaccination in adolescents. abstract, RESULTS Same sentence: 92.3% (34.3-99.1) for 2 doses in adolescents (next record).
Serogroup B invasive meningococcal disease severity: any invasive disease strain: serogroup B case definition: Notified serogroup B IMD, South Australia adolescent programme	adolescents aged 15-18 years country: Australia (South Australia) period: 2019-2023 12-17y	4CMenB (Bexsero) platform: multicomponent recombinant protein plus OMV doses: 2 time since vaccination: up to 5 years vs unvaccinated (screening and case-control methods)	92.3 (34.3–99.1) VE (%)	screening method	Wang et al. 2025 Clin Infect Dis quote VE against MenB disease for the 3-dose schedule was 98.5% (95% CI, 81.9%-99.9%) in children and 92.3% (34.3%-99.1%) for the 2-dose vaccination in adolescents. abstract, RESULTS
Serogroup B invasive meningococcal disease severity: any invasive disease strain: serogroup B case definition: Notified serogroup B IMD, South Australia programme, 3-year evaluation	infants and children (childhood programme) country: Australia (South Australia) period: 2018-2021 Infant <1y1-4y	4CMenB (Bexsero) platform: multicomponent recombinant protein plus OMV doses: 2 time since vaccination: up to 3 years vs unvaccinated (screening and case-control methods)	90.7 (6.9–99.1) VE (%)	screening method	Wang et al. 2023 J Infect quote Two-dose VE against MenB disease was 90.7% (95%CI 6.9-99.1%) for the childhood programme and 83.5% (95%CI 0-98.2%) for the adolescent programme. abstract, RESULTS Same sentence: 83.5% (0-98.2) for the adolescent programme, lower bound at zero. No cases in infants who had received three doses.
Serogroup W invasive meningococcal disease (programme impact) severity: any invasive disease strain: serogroup W (ST-11 complex) case definition: Laboratory-confirmed MenW cases in adolescents vs predicted from pre-programme trends	adolescents aged 14-18 years country: England period: 2015-2019 12-17y18-49y	MenACWY conjugate (UK adolescent programme) platform: polysaccharide-protein conjugate doses: 1 vs predicted cases from 2010-11 to 2014-15 trends	0.35 (0.17–0.76) incidence rate ratio (observed vs predicted)	surveillance	Campbell et al. 2022 Lancet Child Adolesc Health quote Significant reductions were observed among adolescents aged 14-18 years for MenW (incidence rate ratio [IRR] 0·35 [95% CI 0·17-0·76]) and MenY (0·21 [0·07-0·59]) cases, with a non-significant reduction in MenC cases (0·11 [0·01-1·01]). abstract, FINDINGS Same sentence gives IRRs for MenY (significant) and MenC (not significant). Programme impact, direct plus indirect, achieved with moderate uptake in school leavers.
Serogroup W invasive meningococcal disease (programme impact) severity: any invasive disease strain: serogroup W case definition: IMD-W incidence before (July 2017-March 2018) vs after (July 2019-March 2020) MenACWY implementation	all ages country: Netherlands period: 2017-2020 All ages	MenACWY-TT (toddler dose plus 14-18-year campaign) platform: polysaccharide-tetanus toxoid conjugate doses: 1 vs pre-implementation incidence	61 (40–74) reduction in incidence rate (%)	surveillance	Ohm et al. 2022 Clin Infect Dis quote RESULTS: Overall, the IMD-W incidence rate declined by 61% (95% confidence interval [CI], 40 to 74). abstract, RESULTS Larger decline in vaccine-eligible groups than in non-eligible groups; the latter may be indirect protection but natural fluctuation cannot be excluded.
Serogroup C, W or Y meningococcal disease incidence trend (programme impact) severity: any invasive disease strain: serogroups C, W, Y combined case definition: Confirmed and probable CWY cases in NNDSS, Poisson segmented regression	16 to 22 years country: United States period: 2011-2017 (post-booster period) 12-17y18-49y	MenACWY (primary dose at 11-12 years plus booster at 16) platform: polysaccharide-protein conjugate doses: 2 vs annual decline of 10.6% (6.8-14.3) in the same age group during the post-primary-dose period	35.6 (29.3–41.0) annual percentage decline in incidence (%)	surveillance	Mbaeyi et al. 2020 JAMA Pediatr quote Incidence of serogroup CWY meningococcal disease among adolescents aged 11 to 15 years decreased by 16.3% (95% CI, 12.1%-20.3%) annually during the prevaccine period and 27.8% (95% CI, 20.6%-34.4%) during the post-primary dose period (P = .02); among adolescents aged 16 to 22 years, the incidence decreased by 10.6% (95% CI, 6.8%-14.3%) annually in the post-primary dose period and 35.6% (95% CI, 29.3%-41.0%) annually in the post-booster dose period (P < .001). abstract, RESULTS A trend-acceleration analysis, not a VE. Incidence was already falling before the vaccine, so the vaccine cannot explain the whole decline.
Serogroup B invasive meningococcal disease (programme impact) severity: any invasive disease strain: serogroup B case definition: MenB cases in the vaccine-eligible cohort vs equivalent cohorts in the previous 4 years	vaccine-eligible infants country: England period: September 2015 to June 2016 Infant <1y	4CMenB (Bexsero) platform: multicomponent recombinant protein plus OMV doses: 2 vs equivalent age cohorts in the 4 pre-vaccine years	0.50 (0.36–0.71) incidence rate ratio vs pre-vaccine cohorts	surveillance	Parikh et al. 2016 Lancet quote Compared with the prevaccine period, there was a 50% incidence rate ratio (IRR) reduction in MenB cases in the vaccine-eligible cohort (37 cases vs average 74 cases; IRR 0·50 [95% CI 0·36-0·71]; p=0·0001), irrespective of the infants' vaccination status or predicted MenB strain coverage. abstract, FINDINGS Reduction irrespective of individual vaccination status or predicted strain coverage; similar after adjusting for trends in ineligible children.
Serogroup B invasive meningococcal disease (programme impact, 3 years) severity: any invasive disease strain: serogroup B case definition: MenB cases in vaccine-eligible cohorts vs expected from the 4-year prevaccination period	vaccine-eligible children under 5 years country: England period: September 2015 to August 2018 Infant <1y1-4y	4CMenB (Bexsero) platform: multicomponent recombinant protein plus OMV doses: 2 priming plus 12-month booster vs expected incidence from prevaccination cohorts	0.25 (0.19–0.36) incidence rate ratio (observed vs expected)	surveillance	Ladhani et al. 2020 N Engl J Med quote From September 2015 through August 2018, the incidence of meningococcal group B disease in England (average annual birth cohort, approximately 650,000 infants) was significantly lower in vaccine-eligible cohorts than the expected incidence (63 observed cases as compared with 253 expected cases; incidence rate ratio, 0.25; 95% confidence interval [CI], 0.19 to 0.36), with a 75% reduction in age groups that were fully eligible for vaccination. abstract, RESULTS Three-quarters reduction in fully eligible age groups; several hundred cases estimated prevented. Uptake was high.
Serogroup W invasive meningococcal disease (cross-protection, programme impact) severity: any invasive disease strain: serogroup W (ST-11 clonal complex) case definition: Confirmed MenW cases in age cohorts fully eligible for 4CMenB vs predicted, Poisson model	children under 5 fully eligible for 4CMenB country: England period: 4 years before vs 4 years after September 2015 Infant <1y1-4y	4CMenB (Bexsero) platform: multicomponent recombinant protein plus OMV doses: 2 or 3 vs predicted cases from pre-programme trends, adjusted for the adolescent MenACWY programme's indirect effect	69 reduction in MenW cases vs predicted (%)	surveillance	Ladhani et al. 2021 Clin Infect Dis quote RESULTS: Model estimates showed 69% (adjusted incidence rate ratio [aIRR], .31; 95% CI, .20-.67) and 52% (aIRR, .48; 95% CI, .28-.81) fewer MenW cases than predicted among age-cohorts that were fully- and partly-eligible for 4CMenB, respectively. abstract, RESULTS Adjusted IRR with its interval is in the quote; a smaller reduction in partly eligible cohorts. First real-world evidence that 4CMenB antigens protect against a non-B serogroup; model-based attribution.
Serogroup B invasive meningococcal disease (programme impact) severity: any invasive disease strain: serogroup B case definition: Notified serogroup B IMD, adjusted for trends in non-eligible cohorts	12 weeks to 11 months country: Australia (South Australia) period: 2 years after October 2018 Infant <1y	4CMenB (Bexsero) platform: multicomponent recombinant protein plus OMV doses: 2 to 3 vs equivalent age cohort in pre-programme years, adjusted for non-eligible cohort trends	0.40 (0.23–0.69) adjusted incidence rate ratio vs pre-programme years	surveillance	Wang et al. 2022 Lancet Infect Dis quote 2 years after implementation of the childhood vaccination programme, incidence of serogroup B meningococcal disease was significantly reduced compared with before programme implementation in infants aged 12 weeks to 11 months (adjusted IRR [aIRR] 0·40 [95% CI 0·23-0·69], p=0·0011), but not in those aged 1 year (0·79 [0·16-3·87], p=0·77), 2 years (0·75 [0·18-3·14], p=0·70), or 4 years (3·00 [0·47-18·79], p=0·24). aIRRs were not calculable in those aged 3 or 5 years because of no cases occurring after programme implementation. aIRR for serogroup B meningococcal disease was 0·27 (0·06-1·16, p=0·078) in adolescents aged 15-18 years 2 years after implementation of the adolescent and young adult programme, and 1·20 (0·70-2·06, p=0·51) in those aged 19-21 years in the first year. abstract, FINDINGS Not significant at age 1 (0.79), 2 (0.75) or 4 years (3.00) with very few cases. COVID-19 distancing may have contributed to declines in year 2.
Serogroup B invasive meningococcal disease (programme impact, 5 years) severity: any invasive disease strain: serogroup B case definition: Notified serogroup B IMD incidence in infants vs pre-programme	infants under 1 year country: Australia (South Australia) period: 2018-2023 Infant <1y	4CMenB (Bexsero) platform: multicomponent recombinant protein plus OMV doses: 2 to 3 vs pre-programme incidence in the same age group	72.7 (38.0–88.0) relative reduction in incidence (%)	surveillance	Wang et al. 2025 Clin Infect Dis quote RESULTS: Relative reductions of 72.7% (95% confidence interval [CI], 38.0%-88.0%) and 76.2% (41.6%-90.3%) in the incidence of MenB disease were observed in infants aged <1 year and adolescents aged 15-18 years, respectively. abstract, RESULTS Same sentence: 76.2% (41.6-90.3) in adolescents aged 15-18.
Serogroup B invasive meningococcal disease (programme impact after adolescent cluster-RCT vaccination) severity: any invasive disease strain: serogroup B case definition: Serogroup B IMD cases in 16-19-year-olds vs expected from 2003-2016 trend	16 to 19 years country: Australia (South Australia) period: 2017-2019 n: 30,522 students received at least 1 dose 12-17y18-49y	4CMenB (Bexsero) platform: multicomponent recombinant protein plus OMV doses: 1 or 2 vs expected cases from the pre-trial time series (cases had been rising 10% per year)	71 (15–90) reduction in cases vs expected (%)	surveillance	McMillan et al. 2021 Clin Infect Dis quote This translated to an overall reduction in the number of serogroup B IMD cases of 71% (95% CI, 15%-90%, P = .02). abstract, RESULTS No serogroup B cases in vaccinated adolescents. Interrupted time series, not a VE; contrasts with the null carriage result in the same trial (next record).
Suspected meningitis (all causes, clinical case definition) severity: any suspected meningitis case definition: Suspected meningitis cases in WHO IST surveillance, vaccinated vs unvaccinated populations, negative binomial regression	1 to 29 years (campaign target) and whole population country: Benin, Burkina Faso, Chad, Cote d'Ivoire, Ghana, Mali, Niger, Nigeria, Togo setting: meningitis belt, LMIC period: 2005-2015 All ages	MenAfriVac (PsA-TT) platform: serogroup A polysaccharide-tetanus toxoid conjugate doses: 1 vs unvaccinated populations (districts/periods before campaigns)	57 (55–59) reduction in incidence of suspected meningitis (%)	surveillance	Trotter et al. 2017 Lancet Infect Dis quote FINDINGS: The incidence of suspected meningitis cases declined by 57% (95% CI 55-59) in vaccinated compared with unvaccinated populations, with some heterogeneity observed by country. abstract, FINDINGS Heterogeneity by country. Confirmed group A disease fell almost completely in fully vaccinated populations (next record); the risk of a district reaching the epidemic threshold also fell.
Laboratory-confirmed serogroup A meningococcal meningitis severity: any confirmed disease strain: serogroup A case definition: Confirmed group A cases in fully vaccinated populations, nine-country surveillance	all ages in fully vaccinated populations country: nine meningitis-belt countries setting: meningitis belt, LMIC period: 2010-2015 All ages	MenAfriVac (PsA-TT) platform: serogroup A polysaccharide-tetanus toxoid conjugate doses: 1 vs unvaccinated populations	99 reduction in incidence (%)	surveillance	Trotter et al. 2017 Lancet Infect Dis quote In fully vaccinated populations, the incidence of confirmed group A disease was reduced by more than 99%. abstract, FINDINGS Reported as "more than 99%"; no interval given.
Suspected meningitis (all causes) severity: any suspected meningitis case definition: Suspected meningitis in national surveillance, first year after campaign vs 14 pre-vaccine years	all ages (national) country: Burkina Faso setting: meningitis belt, LMIC; national campaign of 11.4 million aged 1-29 period: 2011 vs 1997-2010 All ages	MenAfriVac (PsA-TT) platform: serogroup A polysaccharide-tetanus toxoid conjugate doses: 1 vs pre-vaccine years	0.29 (0.28–0.30) hazard ratio for meningitis, post- vs pre-vaccine	surveillance	Novak et al. 2012 Lancet Infect Dis quote After vaccine introduction, there was a 71% decline in risk of meningitis (hazard ratio 0·29, 95% CI 0·28-0·30, p<0·0001) and a 64% decline in risk of fatal meningitis (0·36, 0·33-0·40, p<0·0001). abstract, FINDINGS Same sentence: 64% decline in risk of fatal meningitis (HR 0.36, 0.33-0.40). A single post-vaccine year; epidemic cycles make before-after comparisons uncertain.
Laboratory-confirmed serogroup A meningococcal meningitis severity: any confirmed disease strain: serogroup A case definition: Confirmed NmA meningitis in enhanced laboratory surveillance	all ages (national) country: Burkina Faso setting: meningitis belt, LMIC period: 2011 vs 2007-2010 All ages	MenAfriVac (PsA-TT) platform: serogroup A polysaccharide-tetanus toxoid conjugate doses: 1 vs pre-vaccine years	0.002 (0.0004–0.02) cumulative incidence ratio, post- vs pre-vaccine	surveillance	Novak et al. 2012 Lancet Infect Dis quote The incidence of laboratory-confirmed serogroup A N meningitidis dropped significantly to 0·01 per 100 000 individuals per year, representing a 99·8% reduction in the risk of meningococcal A meningitis (CIR 0·002, 95% CI 0·0004-0·02, p<0·0001). abstract, FINDINGS Incidence fell to a very low rate; no serogroup A cases in vaccinated people; epidemics eliminated in the first year.
Probable meningococcal meningitis in unvaccinated infants (indirect protection) severity: any probable disease case definition: Probable meningococcal meningitis in children under 1 year, who were ineligible for the campaign	under 1 year (not vaccinated) country: Burkina Faso setting: meningitis belt, LMIC period: 2011 vs pre-vaccine Infant <1y	MenAfriVac (PsA-TT) given to 1-29-year-olds (infants themselves unvaccinated) platform: serogroup A polysaccharide-tetanus toxoid conjugate doses: 0 (indirect protection) vs pre-vaccine years	0.46 (0.24–0.86) cumulative incidence ratio, post- vs pre-vaccine	surveillance	Novak et al. 2012 Lancet Infect Dis quote We identified a statistically significant decline in risk of probable meningococcal meningitis across the age group targeted for vaccination (62%, cumulative incidence ratio [CIR] 0·38, 95% CI 0·31-0·45, p<0·0001), and among children aged less than 1 year (54%, 0·46, 0·24-0·86, p=0·02) and people aged 30 years and older (55%, 0·45, 0·22-0·91, p=0·003) who were ineligible for vaccination. abstract, FINDINGS Herd effect: a 54% decline in an unvaccinated age group; a similar 55% decline in people aged 30 and over.

Sequelae of invasive meningococcal disease (hearing loss, amputation, neurological and psychological deficits) Neisseria meningitidis

Post-acute and long-term sequelae

What can follow the acute illness: chronic disease, disability, cancers, congenital syndromes, post-infectious conditions.

Outcome (O)	Population (P)	Comparator	Estimate	Design (S)	Source
Long-term sequelae after IMD severity: any long-term sequela case definition: IMD survivors, high-income countries	all ages vaccination status: not reported country: high-income countries period: literature 2001-2016 All ages	vs none (proportion among survivors)	10 to 20 proportion of survivors (%) per IMD survivor	systematic review	Olbrich et al. 2018 Infect Dis Ther quote INTRODUCTION: Invasive meningococcal disease (IMD, septicaemia and/or meningitis) has a severe acute and long-term burden: 5-10% of patients die within 48 h, and long-term sequelae have been reported in 10-20% of survivors. abstract, INTRODUCTION Background range quoted by the review; GSK-funded.
Amputation after IMD severity: amputation case definition: Physical sequelae reported across 31 studies, mostly childhood IMD	children (up to 8%); adolescents and adults (3%) vaccination status: not reported country: high-income countries period: literature 2001-2016 Infant <1y1-4y5-11y12-17y18-49y	vs none (proportion among survivors)	8 proportion of survivors with amputation (%), upper bound in children per IMD survivor	systematic review	Olbrich et al. 2018 Infect Dis Ther quote Physical sequelae included: amputations (up to 8% of children, 3% adolescents/adults) and skin scars (up to 55% of children, 18% adolescents, 2% adults). abstract, RESULTS Maximum reported across studies, not a pooled estimate; same sentence gives skin scars up to 55% of children.
Hearing loss after IMD severity: hearing loss case definition: Neurologic sequelae reported across 31 studies	infants (up to 19%), children 13%, adolescents 12%, adults 8% vaccination status: not reported country: high-income countries period: literature 2001-2016 Infant <1y1-4y5-11y12-17y18-49y	vs none (proportion among survivors)	19 proportion of survivors with hearing loss (%), upper bound in infants per IMD survivor	systematic review	Olbrich et al. 2018 Infect Dis Ther quote Neurologic sequelae included: hearing loss (up to 19% of infants, 13% children, 12% adolescents, 8% adults). abstract, RESULTS Maximum across studies by age group; hearing loss is the most consistently measured sequela.
Permanent sequelae (hearing loss, neurologic damage, limb loss) after IMD severity: permanent disability case definition: Survivors of invasive meningococcal disease	all ages vaccination status: mixed country: United States period: current (Pink Book) All ages	vs none (proportion among survivors)	20 proportion of survivors (%), upper bound per IMD survivor	expert body	cdc.gov quote As many as 20% of survivors have permanent sequelae, such as hearing loss, neurologic damage, or loss of a limb. Clinical Features section Expert-body ceiling figure ("as many as"); no comparator group.
Long-term sequelae (neurologic disability, limb or digit loss, hearing loss) after IMD severity: long-term disability case definition: Survivors of meningococcal disease	all ages vaccination status: mixed country: United States period: ACIP summary, 2020 All ages	vs none (proportion among survivors)	10 to 20 proportion of survivors (%) per IMD survivor	expert body	cdc.gov quote Even with appropriate antimicrobial therapy, the overall case-fatality ratio in the United States is 15%, and 10%–20% of survivors have long-term sequelae such as neurologic disability, limb or digit loss, or hearing loss ( 22 , 23 ). Background, Meningococcal Disease
Bilateral sensorineural hearing loss (>=40 dB) after serogroup B meningococcal disease severity: hearing loss strain: serogroup B case definition: Culture- or PCR-confirmed MenB disease survivors from the UK National Meningococcal Registry, assessed with validated instruments	1 month to 13 years at disease; mean 6.5 years at assessment vaccination status: not reported country: United Kingdom period: 2008-2010 n: 245 cases, 328 controls Infant <1y1-4y5-11y12-17y	vs age- and sex-matched controls recruited through the family doctor	4.8 (1.3–17.4) matched OR vs age- and sex-matched community controls per survivor	case-control	Viner et al. 2012 Lancet Neurol quote In the full sample, children who had serogroup B meningococcal disease were more likely than controls to have bilateral sensorineural hearing loss of 40 dB or more (unmatched 11 [5%] of 232 children with meningococcal disease vs three [<1%] of 318 controls; matched odds ratio [OR] 4·8, 95% CI 1·3 to 17·4, p=0·02), lower full-scale IQ (matched mean 99·5 for children with meningococcal disease and 107·2 for controls; matched coefficient -7·6, 95% CI -9·9 to -5·4, p<0·0001), and psychological disorders (61 [26%] of 235 children with meningococcal disease vs 33 (10%) of 322 controls; matched full sample OR 2·6, 1·6 to 4·2, p<0·0001). abstract, FINDINGS 5% of survivors vs <1% of controls. Controls were matched on age and sex only; residual confounding by socioeconomic status possible, though the researchers were masked to disease status.
Psychological disorders after serogroup B meningococcal disease severity: psychological disorder strain: serogroup B case definition: MOSAIC MenB survivors, validated instruments	1 month to 13 years at disease vaccination status: not reported country: United Kingdom period: 2008-2010 n: 235 cases, 322 controls Infant <1y1-4y5-11y12-17y	vs age- and sex-matched community controls	2.6 (1.6–4.2) matched OR vs matched controls per survivor	case-control	Viner et al. 2012 Lancet Neurol quote In the full sample, children who had serogroup B meningococcal disease were more likely than controls to have bilateral sensorineural hearing loss of 40 dB or more (unmatched 11 [5%] of 232 children with meningococcal disease vs three [<1%] of 318 controls; matched odds ratio [OR] 4·8, 95% CI 1·3 to 17·4, p=0·02), lower full-scale IQ (matched mean 99·5 for children with meningococcal disease and 107·2 for controls; matched coefficient -7·6, 95% CI -9·9 to -5·4, p<0·0001), and psychological disorders (61 [26%] of 235 children with meningococcal disease vs 33 (10%) of 322 controls; matched full sample OR 2·6, 1·6 to 4·2, p<0·0001). abstract, FINDINGS 26% of survivors vs 10% of controls.
Major disabling deficit (physical, cognitive or psychological) after serogroup B meningococcal disease severity: major disability strain: serogroup B case definition: MOSAIC MenB survivors	1 month to 13 years at disease vaccination status: not reported country: United Kingdom period: 2008-2010 n: 244 cases, 328 controls Infant <1y1-4y5-11y12-17y	vs age- and sex-matched community controls	5.0 (2.0–12.6) matched OR vs matched controls per survivor	case-control	Viner et al. 2012 Lancet Neurol quote Major disabling deficits were identified in 21 (9%) of 244 children with meningococcal disease compared with six (2%) of 328 controls (matched OR 5·0, 2·0 to 12·6, p=0·001). abstract, FINDINGS Nine percent of survivors vs two percent of controls; any deficit is a separate record.
One or more deficits in physical, cognitive or psychological functioning after serogroup B meningococcal disease severity: any deficit strain: serogroup B case definition: MOSAIC MenB survivors	1 month to 13 years at disease vaccination status: not reported country: United Kingdom period: 2008-2010 n: 244 cases, 328 controls Infant <1y1-4y5-11y12-17y	vs age- and sex-matched community controls	2.7 (1.8–4.1) matched OR vs matched controls per survivor	case-control	Viner et al. 2012 Lancet Neurol quote Deficits were identified in 87 (36%) of 244 children with serogroup B meningococcal disease and 49 (15%) of 328 controls (matched OR 2·7, 1·8 to 4·1, p<0·0001). abstract, FINDINGS 36% of survivors vs 15% of controls.
Full-scale IQ after serogroup B meningococcal disease severity: cognitive deficit strain: serogroup B case definition: MOSAIC MenB survivors	1 month to 13 years at disease vaccination status: not reported country: United Kingdom period: 2008-2010 n: 245 cases, 328 controls Infant <1y1-4y5-11y12-17y	vs age- and sex-matched community controls	-7.6 (-9.9–-5.4) matched mean difference in full-scale IQ points vs controls per survivor	case-control	Viner et al. 2012 Lancet Neurol quote In the full sample, children who had serogroup B meningococcal disease were more likely than controls to have bilateral sensorineural hearing loss of 40 dB or more (unmatched 11 [5%] of 232 children with meningococcal disease vs three [<1%] of 318 controls; matched odds ratio [OR] 4·8, 95% CI 1·3 to 17·4, p=0·02), lower full-scale IQ (matched mean 99·5 for children with meningococcal disease and 107·2 for controls; matched coefficient -7·6, 95% CI -9·9 to -5·4, p<0·0001), and psychological disorders (61 [26%] of 235 children with meningococcal disease vs 33 (10%) of 322 controls; matched full sample OR 2·6, 1·6 to 4·2, p<0·0001). abstract, FINDINGS Matched means 99.5 (cases) vs 107.2 (controls). Controls may be positively selected (recruited via GP), which would exaggerate the gap.
Disabling amputation after serogroup B meningococcal disease severity: amputation strain: serogroup B case definition: MOSAIC MenB survivors	1 month to 13 years at disease vaccination status: not reported country: United Kingdom period: 2008-2010 n: 239 cases Infant <1y1-4y5-11y12-17y	vs controls (none of 322 had amputations)	1 proportion of survivors (%) per survivor	case-control	Viner et al. 2012 Lancet Neurol quote Disabling amputations were noted in three (1%) of 239 children who had serogroup B meningococcal disease compared with none of the 322 controls. abstract, FINDINGS
Any sequela months after serogroup C meningococcal meningitis epidemic severity: any sequela strain: serogroup C (confirmed subset 18%) case definition: Notified suspected cases traced at home; standardised questionnaire and focused examination	all ages vaccination status: not reported country: Niger setting: meningitis belt epidemic, LMIC period: 2022 n: 521 survivors All ages	vs none (proportion among survivors)	12 proportion of survivors (%) per survivor	cohort	Idrissa et al. 2025 PLoS One quote Among surviving cases, the prevalence of sequelae was 12%, and among survivors of confirmed NmC meningitis, 18%. abstract, RESULTS Same sentence: 18% among survivors of PCR-confirmed NmC meningitis. Most common sequelae hearing loss 6%, paralysis 3%, epilepsy 2% (next record). Suspected-case denominator includes non-meningococcal meningitis.
Hearing loss after serogroup C meningococcal meningitis epidemic severity: hearing loss strain: serogroup C case definition: Survivors traced at home after the 2022 epidemic	all ages vaccination status: not reported country: Niger setting: meningitis belt epidemic, LMIC period: 2022 All ages	vs none (proportion among survivors)	6 proportion of survivors (%) per survivor	cohort	Idrissa et al. 2025 PLoS One quote The most common sequelae were hearing loss (6%), paralysis (3%) and epilepsy (2%). abstract, RESULTS Paralysis 3% and epilepsy 2% in the same sentence.
Permanent sequelae among children hospitalised with IMD severity: permanent sequelae strain: serogroup B predominant case definition: Meningococcal cases at two tertiary paediatric hospitals (94% group B)	children under 19 years, median 5 years vaccination status: mixed country: Ireland setting: tertiary paediatric hospitals period: 2001-2011 n: 382 cases Infant <1y1-4y5-11y12-17y	vs none (proportion among cases)	9.4 proportion of cases (%) per hospitalised paediatric IMD case	case series	Ó et al. 2016 Arch Dis Child quote Permanent sequelae occurred in 9.4%. abstract, RESULTS Denominator is all cases, not survivors.

Gaps

WHO meningococcal position paper could not be reached (two URLs returned 404); no WHO-sourced record.
ECDC annual epidemiological report: the HTML page cached contains only site navigation and the PDF link was 404, so no ECDC-sourced EU case-fatality or serogroup figures.
No clinical efficacy or effectiveness estimate exists for MenB-FHbp (Trumenba); licensure rests on hSBA immunogenicity. Only a persistence study is recorded, flagged as a surrogate.
No case-control or cohort vaccine-effectiveness estimate for MenAfriVac against confirmed serogroup A disease was found; impact is recorded from surveillance (IRR / HR) only.
MenACWY-CRM and MenACWY-TT direct VE against disease in adolescents (as opposed to MenACWY-D in Cohn 2017) not found as a primary estimate; the England MenACWY programme estimate is for MenCWY combined.
No controlled safety study (SCCS/cohort) for meningococcal vaccines was cached; the GBS figure for MenACWY-D sits only in a commentary and is not recorded.
Trotter 2004 Lancet (MenC VE falling after 1 year in routine infants) has no numbers in its abstract; the quantitative waning estimates come from Campbell 2010 and the Spanish screening-method studies instead.
Pre-vaccine (pre-1999) UK serogroup B and C incidence by age band and serogroup-specific sequelae proportions (W vs B) were searched and not found as abstract-level figures.
Sequelae proportions among adult survivors (beyond the ranges in Olbrich 2018) and in LMIC settings other than the Niger 2022 epidemic were not found.
Effectiveness in immunocompromised people: only the eculizumab breakthrough series (incidence multiplier, case counts) was found; no VE estimate in HIV, asplenia or complement deficiency.

Flags for review

Wang 2019 pooled CFRs by serogroup (B 6.9%, C 12.0%, W 12.8%, Y 10.8%) come from national surveillance data in high-income countries 2000-2018; they must not be applied to the meningitis belt or combined with incidence figures from other records to compute deaths.
Several MenB effectiveness estimates have confidence intervals that cross zero (Ladhani 2020: 52.7% [-33.5 to 83.2] and 59.1% [-31.1 to 87.2]; Ohm 2022 toddler MenACWY VE 92% [-20 to 99.5]; MenB-4C Quebec 79% [-231 to 99]). The point estimates are recorded as reported; readers should weigh the intervals.
The 4CMenB adolescent carriage RCT (Marshall 2020, aOR 1.02) found no effect on carriage, while the same programme's disease impact (McMillan 2021, 71% reduction) was positive: herd protection from 4CMenB is not supported, direct protection is. Do not merge these.
Novak 2012 reports Burkina Faso's pre-vaccine 14-year totals (148,603 suspected cases, 17,965 deaths) as counts of suspected (not laboratory-confirmed) meningitis of all causes; not a serogroup A figure and not a rate.
Patel 2005 Cochrane (summary efficacy 95%) is for plain serogroup A POLYSACCHARIDE vaccine, not the MenAfriVac conjugate; included for historical context only and labelled as such in product=.
MenB-FHbp record is an immunogenicity surrogate (hSBA >= LLOQ), not disease protection; the pivotal phase 3 trial (Ostergaard 2017) was not retrieved by the searches run and should be added by a reviewer.
CDC Pink Book and ACIP 2020 give the US overall CFR as "10% to 15%" and "15%" respectively while NNDSS 2006-2015 (MacNeil 2018) gives 14.9%; the Wang 2019 international pooled CFR is 8.3%. Different denominators and eras; show side by side, do not average.
The websource tool failed on the Pink Book with a cp1252 encoding error until run with PYTHONUTF8=1; the cached text is complete (49,692 chars) but a reviewer may want to confirm the tool's default encoding is fixed for other agents.

Search log (42 searches)

meningococcal conjugate vaccine effectiveness MenC United Kingdom waning · PubMed → Findlow 2019 Euro Surveill (MenC England 1998/99-2015/16) and antibody-persistence trials
4CMenB effectiveness infants England Parikh · PubMed → Parikh 2016 Lancet, Ladhani 2020 NEJM, Ladhani 2021 CID (MenW cross-protection)
invasive meningococcal disease case fatality serogroup sequelae systematic review · PubMed → only a MenW manifestations review and an India consensus; CFR meta-analysis found via a later search
MenAfriVac impact meningitis belt serogroup A incidence · PubMed → Trotter 2017 Lancet ID (nine countries), Kristiansen 2013 carriage, Novak 2012 Burkina Faso found later
MenACWY adolescent vaccine effectiveness United States serogroup · PubMed → Cohn 2017 Pediatrics case-control (MenACWY-D); rest modelling/cost-effectiveness
meningococcal disease sequelae survivors hearing loss amputation meta-analysis · PubMed → no hits with that wording; sequelae reviews found with "long-term sequelae survivors systematic review"
invasive meningococcal disease incidence United States 2014 2018 serogroup case-fatality · PubMed → no hits with that wording
MenB-FHbp effectiveness OR efficacy serogroup B · PubMed → only immunogenicity/persistence studies and reviews; no clinical efficacy or effectiveness estimate for MenB-FHbp
meningococcal conjugate vaccine carriage herd immunity adolescents · PubMed → Maiden 2008 (MenC carriage), Carr 2022 (UK MenACWY carriage), Campbell 2010, Kristiansen 2013, Mbaeyi 2020
4CMenB South Australia carriage cluster randomised · PubMed → Marshall 2020 NEJM (B Part of It, null carriage result), McMillan 2021 CID (disease impact)
MenC conjugate vaccine effectiveness England waning Trotter · PubMed → Borrow 2013 review only; Trotter 2004 Lancet found with a later query (abstract carries no numbers)
meningococcal serogroup B vaccine effectiveness case-control Ladhani OR Castilla OR Rodrigues OR Wang · PubMed → Lodi 2023 JAMA Netw Open (Italy); Castilla 2023 NEJM and Wang 2022/2023/2025 found via "case-control children"
meningococcal disease long-term sequelae survivors systematic review · PubMed → Olbrich 2018, Shen 2022, Strifler 2016 systematic reviews
meningococcal disease United States surveillance 2006 2015 incidence case fatality MMWR · PubMed → no hits; MacNeil 2018 CID found via "ABCs incidence case fatality MacNeil OR Mbaeyi"
MenB-FHbp vaccine effectiveness real-world · PubMed → no relevant hits
meningococcal serogroup B vaccine effectiveness case-control children · PubMed → Castilla 2023 NEJM (Spain), Wang 2022 Lancet ID, Wang 2023 J Infect, Wang 2025 CID (South Australia), Harder 2017 OMV review
meningococcal ACWY vaccine effectiveness adolescents England MenW · PubMed → Campbell 2022 Lancet Child Adolesc Health
meningococcal disease Europe ECDC epidemiology serogroup case fatality · PubMed → Greece and Spain outbreak papers only; Whittaker 2017 (EU/EEA 2004-2014) found via "Whittaker" query
meningococcal C conjugate vaccine effectiveness waning Spain OR Netherlands OR Canada · PubMed → Tin Tin Htar 2020 systematic review; Spanish VE papers found via "Larrauri OR Garrido-Estepa"
Viner outcomes of invasive meningococcal serogroup B disease in children and adolescents case-control · PubMed → Viner 2012 Lancet Neurol (MOSAIC)
meningococcal disease United States ABCs incidence case fatality 2006 2015 MacNeil OR Mbaeyi · PubMed → MacNeil 2018 CID, Mbaeyi 2020 JAMA Pediatr, Mbaeyi 2019 Pediatrics (college students), ACIP 2020 MMWR
Ramsay efficacy of meningococcal serogroup C conjugate vaccine in teenagers and toddlers in England · PubMed → Ramsay 2001 Lancet
meningococcal disease older adults incidence case fatality serogroup Y · PubMed → Wang 2019 CFR meta-analysis, Guedes 2022 older-adult review, Meiring 2019 South Africa
MenB-FHbp immunogenicity phase 3 adolescents hSBA bivalent rLP2086 Ostergaard · PubMed → Vesikari 2019 persistence study; the pivotal Ostergaard 2017 NEJM trial did not surface in PubMed searches run here
meningococcal disease epidemic Africa serogroup A 1996 cases deaths Burkina Faso incidence · PubMed → Riou 1996 Bull WHO (Niger 1995 epidemic counts)
meningococcal serogroup C conjugate vaccine effectiveness infants England Trotter 2004 · PubMed → Trotter 2004 Lancet (no numbers in abstract), seroprevalence papers
meningococcal disease Burkina Faso epidemic 2007 serogroup A incidence attack rate · PubMed → Novak 2012 Lancet ID (national surveillance 1997-2011), Trotter 2013 seroprevalence
MenAfriVac vaccine effectiveness case-control OR cohort Chad OR Burkina Faso serogroup A disease · PubMed → Viviani 2022 review, Obaro 2020 comment; no case-control VE study for MenAfriVac found
invasive meningococcal disease England epidemiology serogroup case fatality 2010 2019 enhanced surveillance · PubMed → Isitt 2026 J Infect (MenW cohort England)
meningococcal septicaemia children intensive care mortality PICU cohort · PubMed → O Maoldomhnaigh 2016 (Ireland), Boeddha 2018 EUCLIDS (all-cause sepsis, not used)
meningococcal vaccine immunocompromised HIV OR eculizumab OR asplenia effectiveness OR breakthrough · PubMed → McNamara 2017 MMWR (eculizumab)
meningococcal conjugate vaccine safety Guillain-Barre OR adverse events cohort OR self-controlled · PubMed → Myers 2018 commentary only; no controlled safety study cached
meningococcal C conjugate vaccination Spain effectiveness Larrauri OR Garrido-Estepa · PubMed → Garrido-Estepa 2014 and 2015, Larrauri 2005
meningococcal disease Brazil MenC conjugate effectiveness Salvador OR Sao Paulo · PubMed → Cardoso 2015 PLoS One case-control
meningococcal meningitis sequelae hearing loss Africa meningitis belt survivors · PubMed → Idrissa 2025 PLoS One (Niger 2022 NmC epidemic)
serogroup A meningococcal polysaccharide vaccine efficacy trial Africa randomized · PubMed → Patel 2005 Cochrane review found via "Cochrane" query; MenAfriVac immunogenicity analyses
meningococcal vaccine Cochrane systematic review conjugate · PubMed → Conterno 2006 (MenC, no pooled estimate), Patel 2005 (polysaccharide A)
CDC Pink Book chapter 14 meningococcal disease · websource → cached cdc-gov-510a482bd8
ACIP meningococcal vaccination recommendations 2020 MMWR Recomm Rep · websource → cached cdc-gov-261ab11997
WHO meningococcal position paper (WER 2011 and position-paper index page) · websource → both URLs returned HTTP 404; not cached
ECDC invasive meningococcal disease annual epidemiological report 2022 · websource → HTML page cached (navigation only, no data); PDF URL returned 404
CDC meningococcal surveillance and trends page · websource → cached cdc-gov-bef3304b9d (2025 preliminary case count)