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Hepatitis A Hepatitis A virus

Disease risks

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

Outcome (O)	Population (P)	Estimate	Design (S)	Source
Death from hepatitis A (case-fatality) severity: death case definition: Reported hepatitis A cases, all ages	all ages vaccination status: not reported country: United States All ages	0.3 to 0.6 CFR (%) per reported hepatitis A case	expert body	cdc.gov quote Overall case-fatality estimates range from 0.3% to 0.6% for all ages and up to 1.8% among adults age 50 years or older. Complications section CDC Pink Book summary figure; the same sentence gives the higher case-fatality for adults 50 years or older, recorded separately. A range, not a confidence interval.
Death from hepatitis A (case-fatality) in older adults severity: death case definition: Reported hepatitis A cases among adults 50 years or older	adults age 50 years or older vaccination status: not reported country: United States 50-64y65+	1.8 CFR (%) per reported hepatitis A case	expert body	cdc.gov quote Overall case-fatality estimates range from 0.3% to 0.6% for all ages and up to 1.8% among adults age 50 years or older. Complications section Reported as an upper estimate ('up to'). The Pink Book adds that outbreaks concentrated in older people or people with comorbidities can have significantly higher case-fatality.
Death among fulminant hepatitis A cases severity: death case definition: Fulminant hepatitis after hepatitis A infection	all ages vaccination status: not reported country: United States All ages	80 mortality among fulminant cases (%) per fulminant hepatitis A case	expert body	cdc.gov quote Fulminant hepatitis is the most severe rare complication, with mortality estimates up to 80%. Complications section Denominator is fulminant cases, which are rare; do not multiply this by the overall case-fatality or present it as a per-case risk.
Asymptomatic hepatitis A virus infection in young children severity: asymptomatic case definition: HAV infection without symptomatic illness	children younger than 6 years vaccination status: not reported country: United States Infant <1y1-4y5-11y	70 proportion of infections asymptomatic (%) per HAV infection	expert body	cdc.gov quote In children younger than age 6 years, most (70%) infections are asymptomatic. Clinical Features section Explains why young children are a silent source of infection for adults. The proportion symptomatic rises with age; see the adult jaundice record.
Jaundice in symptomatic hepatitis A severity: symptomatic illness with jaundice case definition: Symptomatic HAV infection in older children and adults	older children and adults vaccination status: not reported country: United States 5-11y12-17y18-49y50-64y65+	more than 70 proportion of infected patients with jaundice (%) per HAV infection in older children and adults	expert body	cdc.gov quote In older children and adults, infection is usually symptomatic, with jaundice occurring in more than 70% of patients. Clinical Features section Lower bound ('more than'), no interval. Contrast with the 70% asymptomatic figure for children under 6 in the same chapter.
Hepatitis A as a cause of paediatric liver transplantation severity: liver transplantation case definition: Liver transplants in children attributed to hepatitis A	children vaccination status: not reported country: France and Argentina Infant <1y1-4y5-11y12-17y	10 (France) and 20 (Argentina) proportion of paediatric liver transplants due to HAV (%) per paediatric liver transplant	expert body	Ciocca 2000 Vaccine quote Hepatitis A is the major cause of fulminant hepatitis, and has been reported to account for 10% of liver transplants in children in France and 20% in Argentina. abstract Narrative review (pre-vaccination Argentina); the figures are reported without sources in the abstract. The same abstract gives 64% one-year survival after transplantation.
In-hospital death among hepatitis A hospitalisations severity: death case definition: Hospitalised cases with ICD-9-CM code 070.0/070.1 in the Taiwan National Health Insurance Research Database	all ages vaccination status: not reported country: Taiwan setting: hospital period: 1997-2011 n: 3990 hospitalised cases All ages	16.8 deaths per 1,000 hospitalisations per 1,000 hepatitis A hospitalisations	cohort	Chen et al. 2016 J Viral Hepat quote The overall mortality rate was 16.8 per 1000 hospitalizations. abstract Denominator is hospitalisations, not all infections.
Death among hospitalised hepatitis A cases, by age severity: death case definition: Hospitalised hepatitis A cases, Taiwan National Health Insurance Research Database	aged over 60 years versus aged 0-19 years vaccination status: not reported country: Taiwan setting: hospital period: 1997-2011 n: 3990 hospitalised cases 65+50-64y	14.88 (2.02–109.40) adjusted OR for death vs age 0-19 years per hospitalised case	cohort	Chen et al. 2016 J Viral Hepat quote The aOR and 95% confidence interval [95%CI] for aged 40-59 years and aged over 60 years were 7.89 (1.06-58.98) and 14.88 (2.02-109.40) compared to aged 0-19 years, respectively. abstract Very wide interval. The same sentence gives aOR 7.89 (1.06-58.98) for ages 40-59, which is recorded separately.
Death among hospitalised hepatitis A cases, by age severity: death case definition: Hospitalised hepatitis A cases, Taiwan National Health Insurance Research Database	aged 40-59 years versus aged 0-19 years vaccination status: not reported country: Taiwan setting: hospital period: 1997-2011 n: 3990 hospitalised cases 18-49y50-64y	7.89 (1.06–58.98) adjusted OR for death vs age 0-19 years per hospitalised case	cohort	Chen et al. 2016 J Viral Hepat quote The aOR and 95% confidence interval [95%CI] for aged 40-59 years and aged over 60 years were 7.89 (1.06-58.98) and 14.88 (2.02-109.40) compared to aged 0-19 years, respectively. abstract Same sentence as the over-60 record; both confirm the steep age gradient in hepatitis A mortality.
Death among adults with acute liver failure from hepatitis A severity: death case definition: Anti-HAV IgM positive acute liver failure enrolled in the US Acute Liver Failure Study Group	adults vaccination status: not reported country: United States setting: hospital (ALF study group centres) period: 1998-2005 n: 29 adults 18-49y50-64y65+	14 proportion of HAV acute liver failure patients who died at 3 weeks (%) per HAV-related acute liver failure case	cohort	Taylor et al. 2006 Hepatology quote At 3 weeks follow-up, 16 had spontaneously recovered (55%), 9 underwent transplantation (31%), and 4 had died (14%). abstract Small series. Denominator is acute liver failure, not all hepatitis A; 31% underwent transplantation in the same sentence.
Hepatitis A as a cause of acute liver failure severity: acute liver failure case definition: Patients enrolled in the US Acute Liver Failure Study Group	adults vaccination status: not reported country: United States setting: hospital period: 1998-2005 18-49y50-64y65+	3.1 proportion of acute liver failure cases due to HAV (%) per acute liver failure case	cohort	Taylor et al. 2006 Hepatology quote Acute HAV accounted for 3.1% of patients enrolled in the ALFSG. abstract Describes HAV's share of ALF aetiology, not the risk of ALF among HAV cases. The abstract also reports this proportion fell from 5% to 0.8% over the study period.
Hepatitis A as a cause of paediatric acute liver failure severity: acute liver failure case definition: Hospitalised patients aged 1-20 years with suspected acute liver failure, 9 Latin American centres	1-20 years, median 5 years vaccination status: not reported country: Argentina, Brazil, Chile, Colombia, Costa Rica, Mexico setting: hospital, LMIC period: 2001-2002 n: 88 patients analysed 1-4y5-11y12-17y18-49y	43 proportion of acute liver failure cases anti-HAV IgM positive (%) per paediatric acute liver failure case	cohort	Ciocca et al. 2007 Pediatr Infect Dis J quote A total of 37 individuals (43%) tested positive for anti-hepatitis A virus (HAV) immunoglobulin M (IgM) as marker of acute HAV infection; one was positive for anti-hepatitis B core antigen IgM and negative for hepatitis B surface antigen. abstract Pre-universal-vaccination Latin America. Share of ALF aetiology, not risk per infection.
Death among children with HAV-related acute liver failure severity: death case definition: Anti-HAV IgM positive acute liver failure in 9 Latin American centres	1-20 years, median 5 years vaccination status: not reported country: Argentina, Brazil, Chile, Colombia, Costa Rica, Mexico setting: hospital, LMIC period: 2001-2002 n: 37 anti-HAV IgM positive patients 1-4y5-11y12-17y18-49y	41 mortality among HAV acute liver failure cases (%) per HAV-related acute liver failure case	cohort	Ciocca et al. 2007 Pediatr Infect Dis J quote Mortality rates in the overall study cohort (45%) and for those who tested anti-HAV IgM positive (41%) were similar. abstract Denominator is ALF cases, which are a small fraction of infections (see hepatitis-a-bur-014). Liver transplantation was available at the study centres.
Hospitalisation among outbreak cases, people experiencing homelessness severity: hospitalisation case definition: Hepatitis A-related hospitalisation, age-adjusted log-binomial regression	mean 39.0 years risk group: people experiencing homelessness vaccination status: not reported country: United States setting: community outbreak period: 2016-2019 n: 817 cases 18-49y50-64y	1.3 adjusted risk ratio for hospitalisation vs cases not experiencing homelessness per outbreak-associated case	cohort	Hofmeister et al. 2021 J Infect Dis quote Residence in Michigan (adjusted risk ratio [aRR] = 1.8), being a man who has sex with men (aRR = 1.5), noninjection drug use (aRR = 1.3), and homelessness (aRR = 1.3) were significantly (P < .05) associated with hepatitis A-related hospitalization. abstract, RESULTS Age-adjusted only; residual confounding by comorbidity and by admission practice for people without housing is likely.
Death among outbreak hepatitis A cases with pre-existing non-viral liver disease severity: death case definition: Outbreak-associated hepatitis A deaths vs surviving outbreak cases matched on age and county	mean 53.6 years (cases) and 51.9 years (controls) risk group: pre-existing non-viral liver disease vaccination status: not reported country: United States setting: community outbreak (Kentucky, Michigan, West Virginia) period: 2016-2019 n: 110 deaths and 414 matched controls 18-49y50-64y65+	5.2 adjusted OR for death vs outbreak cases without the condition per outbreak-associated case	case-control	Hofmeister et al. 2021 Hepatology quote Significantly (P < 0.05) higher odds of mortality were associated with preexisting nonviral liver disease (adjusted odds ratio [aOR], 5.2), history of hepatitis B (aOR, 2.4), diabetes (aOR, 2.2), and cardiovascular disease (aOR, 2.2), as well as initial Model for End-Stage Liver Disease (MELD) score ≥ 30 (aOR, 10.0), aspartate aminotransferase (AST)/alanine aminotransferase (ALT) ratio > 2 (aOR, 10.3), and platelet count < 150,000/μL (aOR, 3.7) among hepatitis A outbreak-associated patients in the independent multivariable conditional logistic regression analyses (each model adjusted for sex). abstract, RESULTS Supports vaccinating people with chronic liver disease. Matched on age and county, adjusted for sex only; other comorbidities were modelled separately (hepatitis B aOR 2.4, diabetes 2.2, cardiovascular disease 2.2).
Death among outbreak hepatitis A cases with a history of hepatitis B severity: death case definition: Outbreak-associated hepatitis A deaths vs surviving outbreak cases matched on age and county	mean 53.6 years (cases) and 51.9 years (controls) risk group: history of hepatitis B vaccination status: not reported country: United States setting: community outbreak (Kentucky, Michigan, West Virginia) period: 2016-2019 n: 110 deaths and 414 matched controls 18-49y50-64y65+	2.4 adjusted OR for death vs outbreak cases without the condition per outbreak-associated case	case-control	Hofmeister et al. 2021 Hepatology quote Significantly (P < 0.05) higher odds of mortality were associated with preexisting nonviral liver disease (adjusted odds ratio [aOR], 5.2), history of hepatitis B (aOR, 2.4), diabetes (aOR, 2.2), and cardiovascular disease (aOR, 2.2), as well as initial Model for End-Stage Liver Disease (MELD) score ≥ 30 (aOR, 10.0), aspartate aminotransferase (AST)/alanine aminotransferase (ALT) ratio > 2 (aOR, 10.3), and platelet count < 150,000/μL (aOR, 3.7) among hepatitis A outbreak-associated patients in the independent multivariable conditional logistic regression analyses (each model adjusted for sex). abstract, RESULTS Each comorbidity modelled in a separate conditional logistic regression adjusted for sex; not mutually adjusted.
Death from acute hepatitis A severity: death case definition: Reported acute viral hepatitis cases in the Italian surveillance system	all ages vaccination status: not reported country: Italy setting: national surveillance period: 1985-1994 n: 6,353 hepatitis A cases All ages	0.02 CFR (%) per reported hepatitis A case	surveillance	Stroffolini et al. 1997 Scand J Infect Dis quote One death occurred among the 6,353 (0.02%) hepatitis A cases and 1 among the 909 (0.1%) anti-HCV positive NANB hepatitis cases. abstract Pre-vaccine-era surveillance in a country where most cases were in children and young adults; much lower than the CFR seen in recent adult outbreaks.
Reported hepatitis A incidence in children, pre-vaccine era severity: any reported case case definition: Reported hepatitis A cases per 100,000 population	children 2 through 18 years vaccination status: unvaccinated country: United States setting: national surveillance period: early to mid-1990s 1-4y5-11y12-17y	15 to 20 incidence per 100,000 population per year per 100,000 population	surveillance	cdc.gov quote Historically, children age 2 through 18 years had the highest rates of hepatitis A (15 to 20 cases per 100,000 population in the early to mid-1990s). Secular Trends in the United States Pre-vaccine era (vaccine licensed 1995). Reported cases understate infections because most childhood infections are asymptomatic.
Reported hepatitis A incidence, pre-vaccine baseline severity: any reported case case definition: Cases reported to the National Notifiable Diseases Surveillance System	all ages vaccination status: unvaccinated country: United States setting: national surveillance period: 1990-1998 All ages	10.4 incidence per 100,000 population per 100,000 population	surveillance	Hofmeister et al. 2023 Public Health Rep quote RESULTS: Overall, the rate per 100 000 population of reported cases of hepatitis A virus infection in the United States declined 17.3-fold, from 10.4 during 1990-1998 to 0.6 during 2007-2015, and then increased to 2.8 during 2016-2020. abstract, RESULTS Baseline for the 17.3-fold decline; the 2007-2015 and 2016-2020 rates from the same sentence are hepatitis-a-bur-020 and hepatitis-a-bur-021.
Reported hepatitis A incidence, vaccine era low point severity: any reported case case definition: Cases reported to the National Notifiable Diseases Surveillance System	all ages vaccination status: mixed country: United States setting: national surveillance period: 2007-2015 All ages	0.6 incidence per 100,000 population per 100,000 population	surveillance	Hofmeister et al. 2023 Public Health Rep quote RESULTS: Overall, the rate per 100 000 population of reported cases of hepatitis A virus infection in the United States declined 17.3-fold, from 10.4 during 1990-1998 to 0.6 during 2007-2015, and then increased to 2.8 during 2016-2020. abstract, RESULTS Universal childhood vaccination recommended nationally from 2006. Ecological comparison with the 1990-1998 baseline; sanitation and other trends are not separated out.
Reported hepatitis A incidence during person-to-person outbreaks severity: any reported case case definition: Cases reported to the National Notifiable Diseases Surveillance System	all ages vaccination status: mixed country: United States setting: national surveillance period: 2016-2020 All ages	2.8 incidence per 100,000 population per 100,000 population	surveillance	Hofmeister et al. 2023 Public Health Rep quote RESULTS: Overall, the rate per 100 000 population of reported cases of hepatitis A virus infection in the United States declined 17.3-fold, from 10.4 during 1990-1998 to 0.6 during 2007-2015, and then increased to 2.8 during 2016-2020. abstract, RESULTS Rebound driven by outbreaks among people who use drugs and people experiencing homelessness, populations with low vaccine coverage.
Reported hepatitis A incidence after targeted childhood vaccination severity: any reported case case definition: Cases reported to the National Notifiable Diseases Surveillance System	all ages vaccination status: mixed country: United States setting: national surveillance period: 2003 versus 1990-1997 baseline All ages	2.6 incidence per 100,000 population per 100,000 population	surveillance	Wasley et al. 2005 JAMA quote RESULTS: Between the baseline period (1990-1997) and 2003, overall hepatitis A rates declined 76% to 2.6 per 100,000, significantly lower than previous nadirs in 1983 (9.2/100,000) and 1992 (9.1/ 100,000). abstract, RESULTS Period when routine vaccination was recommended only in 17 higher-incidence states; declines were larger in those states (88%) than elsewhere (53%).
Reported hepatitis A incidence severity: any reported case case definition: Cases reported to the National Notifiable Diseases Surveillance System	all ages vaccination status: mixed country: United States setting: national surveillance period: 2011 (versus 6.0 in 1999) All ages	0.4 incidence per 100,000 population per 100,000 population	surveillance	Ly et al. 2015 J Infect Dis quote RESULTS: During 1999-2011, the incidence of HAV infection declined from 6.0 cases/100 000 to 0.4 cases/100 000. abstract, RESULTS Historic low before the 2016 outbreaks. In 2011 the highest incidence was in persons aged 80 years or older.
Hospitalisation among reported hepatitis A cases severity: hospitalisation case definition: Reported cases with hospitalisation recorded, National Notifiable Diseases Surveillance System	all ages, mean age of hospitalised cases 45.1 years in 2011 vaccination status: mixed country: United States setting: national surveillance period: 2011 All ages	24.5 proportion of reported cases hospitalised (%) per reported hepatitis A case	surveillance	Ly et al. 2015 J Infect Dis quote HAV-related hospitalizations increased from 7.3% in 1999 to 24.5% in 2011. abstract, RESULTS Rose from 7.3% in 1999 as cases shifted to older adults with comorbidities. Proportion of reported cases, which under-ascertains mild infection.
Hospitalisation with hepatitis A as principal diagnosis severity: hospitalisation case definition: National Inpatient Survey discharges with principal ICD-9 hepatitis A diagnosis	all ages, mean age of hospitalised rose from 37.6 to 45.5 years vaccination status: mixed country: United States setting: hospital period: 2010-2011 (versus 0.72 in 2002-2003) All ages	0.29 hospitalisations per 100,000 population per 100,000 population	surveillance	Collier et al. 2015 Hepatology quote Rates of hospitalization for hepatitis A as a principal diagnosis decreased from 0.72/100,000 to 0.29/100,000 (P < 0.0001) and mean age of those hospitalized increased from 37.6 years to 45.5 years (P < 0.0001) during 2002-2011. abstract, RESULTS Population hospitalisation rate, not a per-case proportion. Hospitalised patients became older and more likely to have liver disease over the period.
Deaths with hepatitis A as underlying cause severity: death case definition: US death certificates listing hepatitis A as underlying cause	all ages vaccination status: mixed country: United States setting: national vital statistics period: 1990-2004 All ages	96 average annual deaths (count) per year, national	surveillance	Vogt et al. 2008 J Infect Dis quote RESULTS: Overall, 1436 deaths due to hepatitis A occurred, averaging 96 annually (range, 142 in 1995 to 54 in 2003). abstract, RESULTS A count, not a rate. Chronic liver disease contributed to nearly half of these deaths. Age-adjusted mortality was 32% lower in 2000-2004 than 1990-1995 (hepatitis-a-bur-027).
Hospitalisation during 2017 outbreaks among people experiencing homelessness and people who use drugs severity: hospitalisation case definition: Outbreak-associated HAV cases reported from California, Kentucky, Michigan and Utah	all ages, mostly adults risk group: persons reporting homelessness or injection or non-injection drug use vaccination status: not reported country: United States setting: community outbreak period: 2017 n: 1,521 outbreak-associated cases All ages	71 proportion of cases hospitalised (%) per outbreak-associated case	surveillance	cdc.gov quote During 2017, a total of 1,521 outbreak-associated HAV cases were reported from California, Kentucky, Michigan, and Utah, with 1,073 (71%) hospitalizations and 41 (3%) deaths; most infections were among persons reporting homelessness or injection or non-injection drug use. Secular Trends in the United States Far above the historical hospitalisation proportion for hepatitis A; cases were adults with comorbidities and limited access to care. Deaths (3%) in the same sentence are hepatitis-a-bur-029.
Death during 2017 outbreaks among people experiencing homelessness and people who use drugs severity: death case definition: Outbreak-associated HAV cases reported from California, Kentucky, Michigan and Utah	all ages, mostly adults risk group: persons reporting homelessness or injection or non-injection drug use vaccination status: not reported country: United States setting: community outbreak period: 2017 n: 1,521 outbreak-associated cases All ages	3 CFR (%) per outbreak-associated case	surveillance	cdc.gov quote During 2017, a total of 1,521 outbreak-associated HAV cases were reported from California, Kentucky, Michigan, and Utah, with 1,073 (71%) hospitalizations and 41 (3%) deaths; most infections were among persons reporting homelessness or injection or non-injection drug use. Secular Trends in the United States Several-fold higher than the all-ages CFR in hepatitis-a-bur-001, reflecting an older population with chronic liver disease and drug use.
Hospitalisation during US person-to-person outbreaks severity: hospitalisation case definition: Outbreak-associated hepatitis A cases reported by 33 states with clinical outcome information	all ages, mostly adults risk group: 56% reported drug use, 14% experiencing homelessness vaccination status: not reported country: United States setting: community outbreaks period: August 2016-December 2020 n: 37,553 outbreak-associated cases All ages	61 proportion of cases hospitalised (%) per outbreak-associated case with outcome information	surveillance	Foster et al. 2022 MMWR Morb Mortal Wkly Rep quote Among persons with available risk factor or clinical outcome information, 56% reported drug use, 14% reported experiencing homelessness, and 61% had been hospitalized; 380 outbreak-associated deaths were reported. abstract 380 outbreak-associated deaths were reported in the same analysis. Hospitalisation may partly reflect clinical practice (admitting people without stable housing) rather than severity alone.
Death during US person-to-person outbreaks severity: death case definition: Reported outbreak-associated hepatitis A cases, 37 states	54% aged 30-49 years risk group: drug use (53%) and homelessness or unstable housing (14%) vaccination status: not reported country: United States setting: community outbreaks period: August 2016-December 2023 n: 44,930 outbreak-associated cases 18-49y50-64y65+	1 CFR (%) per outbreak-associated case	surveillance	Hofmeister et al. 2026 J Viral Hepat quote Among 44,930 reported outbreak-associated cases, most occurred among males (62%), non-Hispanic White persons (65%), and those aged 30-49 years (54%); 62% were hospitalised and 1% died. abstract Rounded to a whole percent in the source. 62% hospitalised in the same sentence (hepatitis-a-bur-032).
Hospitalisation during US person-to-person outbreaks severity: hospitalisation case definition: Reported outbreak-associated hepatitis A cases, 37 states	54% aged 30-49 years risk group: drug use (53%) and homelessness or unstable housing (14%) vaccination status: not reported country: United States setting: community outbreaks period: August 2016-December 2023 n: 44,930 outbreak-associated cases 18-49y50-64y65+	62 proportion of cases hospitalised (%) per outbreak-associated case	surveillance	Hofmeister et al. 2026 J Viral Hepat quote Among 44,930 reported outbreak-associated cases, most occurred among males (62%), non-Hispanic White persons (65%), and those aged 30-49 years (54%); 62% were hospitalised and 1% died. abstract Sixty-seven percent of adult cases had a documented indication for hepatitis A vaccination.
Hospitalisation in a random sample of outbreak cases severity: hospitalisation case definition: 10% random sample of outbreak-associated hepatitis A cases in Kentucky, Michigan and West Virginia	mean 39.0 years risk group: 73.2% reported drug use, 14.0% homeless, 29.7% recently incarcerated vaccination status: not reported country: United States setting: community outbreak period: 2016-2019 n: 817 cases 18-49y50-64y	51.8 proportion of cases hospitalised (%) per outbreak-associated case	surveillance	Hofmeister et al. 2021 J Infect Dis quote RESULTS: Participants in the random sample (n = 817) were primarily male (62.5%) with mean age of 39.0 years; 51.8% were hospitalized. abstract, RESULTS Lower than the 61-71% in reported aggregate data, suggesting some over-representation of hospitalised cases in routine reporting, or state differences (Michigan had higher hospitalisation).
Hospitalisation among international travellers with hepatitis A severity: hospitalisation case definition: Confirmed or probable hepatitis A diagnosed at GeoSentinel sites	median 28 years (IQR 19-40) risk group: international travellers vaccination status: unvaccinated country: multiple (GeoSentinel network) setting: travel clinics period: 2008-2020 n: 88 travellers with hospitalisation data 12-17y18-49y50-64y	59 proportion of travellers with hepatitis A hospitalised (%) per traveller with hepatitis A	surveillance	Balogun et al. 2022 J Travel Med quote Among 88 travellers with information available, 59% were hospitalized. abstract, RESULTS Sentinel-site ascertainment favours more severe illness. 98% of travellers with vaccination information were unvaccinated (hepatitis-a-bur-038).
Vaccination status of travellers with hepatitis A severity: any case definition: Confirmed or probable hepatitis A diagnosed at GeoSentinel sites	median 28 years (IQR 19-40) risk group: international travellers vaccination status: unvaccinated country: multiple (GeoSentinel network) setting: travel clinics period: 2008-2020 n: 54 travellers with vaccination information 12-17y18-49y50-64y	98 proportion of cases unvaccinated (%) per traveller with hepatitis A and known vaccination status	surveillance	Balogun et al. 2022 J Travel Med quote RESULTS: Among 254 travellers with hepatitis A (185 confirmed and 69 probable), the median age was 28 years (interquartile range: 19-40), 150 (59%) were male, and among 54 travellers with information available, 53 (98%) were unvaccinated. abstract, RESULTS Only 54 of 254 cases had vaccination information. Indicates travel-associated hepatitis A occurs almost entirely in the unvaccinated, but this is not a vaccine effectiveness estimate because traveller coverage is unknown.
Vaccination status of reported hepatitis A cases after universal toddler vaccination severity: any reported case case definition: Reported hepatitis A cases nationwide with ascertainable vaccination status	all ages vaccination status: unvaccinated country: Israel setting: national surveillance period: 2002-2004 n: 433 cases All ages	97.9 proportion of cases unvaccinated (%) per reported hepatitis A case with known vaccination status	surveillance	Dagan et al. 2005 JAMA quote Of the 433 cases reported nationwide in 2002-2004 in whom vaccination status could be ascertained, 424 (97.9%) received no vaccine and none received 2 doses. abstract, RESULTS No case had received 2 doses. Because coverage was 85-90% in toddlers only, this proportion mixes vaccinated-cohort and older unvaccinated age groups and is not itself a VE estimate.
Fulminant hepatic failure after hepatitis A in children severity: fulminant hepatic failure case definition: Fulminant hepatic failure as a complication of HAV infection in children	children vaccination status: not reported country: Argentina Infant <1y1-4y5-11y12-17y	0.4 proportion of paediatric cases with fulminant hepatic failure (%) per hepatitis A case in children	case series	Cervio et al. 2011 Hepat Med quote The most severe complication in children is fulminant hepatic failure (FHF), estimated to occur in 0.4% of cases; patients with FHF often require a liver transplant (LT). abstract, INTRODUCTION A background estimate cited in the paper's introduction, not a result measured by the study. Check the primary source before quoting it as an Argentine measurement.
Hepatitis A as a cause of paediatric fulminant hepatic failure, pre-vaccination severity: fulminant hepatic failure case definition: Paediatric fulminant hepatic failure admitted to four Buenos Aires centres, Pediatric Acute Liver Failure criteria	children vaccination status: unvaccinated country: Argentina setting: hospital period: March 1993-July 2005 (pre-universal immunisation) n: 165 HAV-associated FHF cases Infant <1y1-4y5-11y12-17y	54.6 proportion of FHF cases caused by HAV (%) per paediatric fulminant hepatic failure case	case series	Cervio et al. 2011 Hepat Med quote RESULTS: During the pre-immunization period, March 1993-July 2005, 54.6% (N = 165) of FHF cases were caused by HAV; HAV-associated FHF cases peaked during 2003-2004. abstract, RESULTS Pre-immunisation period; the post-immunisation share (27.7%) is recorded as hepatitis-a-bur-016. Share of aetiology, not risk per infection.
Hepatitis A as a cause of paediatric fulminant hepatic failure, post-vaccination severity: fulminant hepatic failure case definition: Paediatric fulminant hepatic failure admitted to four Buenos Aires centres	children vaccination status: mixed country: Argentina setting: hospital period: August 2005-December 2008 (post single-dose universal immunisation) n: 18 HAV-associated FHF cases Infant <1y1-4y5-11y12-17y	27.7 proportion of FHF cases caused by HAV (%) per paediatric fulminant hepatic failure case	case series	Cervio et al. 2011 Hepat Med quote During the post-immunization period, August 2005-December 2008, only 27.7% (N = 18) of FHF cases were caused by HAV infection; only one of these patients had received the HAV vaccine (one dose only). abstract, RESULTS Only one of these 18 children had received the vaccine (one dose). No HAV-associated FHF was reported from November 2006 to December 2008.
Change in hepatitis A mortality after vaccination recommendations severity: death case definition: Age-adjusted hepatitis A mortality from death certificates	all ages vaccination status: mixed country: United States setting: national vital statistics period: 2000-2004 versus 1990-1995 All ages	32 relative reduction in age-adjusted mortality rate (%) per population (age-adjusted)	ecological	Vogt et al. 2008 J Infect Dis quote Average rates were 32% lower in the post-vaccination recommendation period than in the prevaccine period (P < .01). abstract, RESULTS Ecological before-after comparison; the decline was larger (45%) in states with vaccination recommendations than without (23%).

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
Prolonged or relapsing hepatitis A severity: prolonged illness case definition: Signs and symptoms persisting or relapsing for up to 6 months after clinical hepatitis A	all ages vaccination status: not reported country: United States All ages	vs none (descriptive proportion among cases)	10 to 15 proportion of symptomatic cases (%) per clinical hepatitis A case follow-up: up to 6 months	expert body	cdc.gov quote Clinical illness usually does not last longer than 2 months, although 10% to 15% of persons have prolonged or relapsing signs and symptoms for up to 6 months. Clinical Features section Hepatitis A does not become chronic; this is the only common post-acute course. No comparator group and no interval. Virus may be excreted during relapse.

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
Clinically apparent hepatitis A severity: symptomatic case definition: Clinically confirmed hepatitis A as defined in the included trials	all ages in the included trials (mostly children) country: multiple n: 41,430 participants in 3 low risk of bias trials All ages	Inactivated hepatitis A vaccine platform: inactivated doses: as per included trials (1 to 3) vs placebo, no intervention or control vaccine	0.09 (0.03–0.30) RR of clinically apparent hepatitis A	meta-analysis 3 randomised trials with low risk of bias	Irving et al. 2012 Cochrane Database Syst Rev quote In the three randomised trials with low risk of bias (all assessing inactivated vaccine), clinically apparent hepatitis A occurred in 9/20,684 (0.04%) versus 92/20,746 (0.44%) participants in the HAV vaccine and control groups respectively (RR 0.09, 95% CI 0.03 to 0.30). abstract, MAIN RESULTS Reported as a risk ratio, not VE; do not convert. Restricted to the three trials judged at low risk of bias.
Clinically apparent hepatitis A severity: symptomatic case definition: Clinically confirmed hepatitis A as defined in the included trials	all ages in the included trials country: multiple n: 732,380 participants All ages	Inactivated or live attenuated hepatitis A vaccine platform: inactivated and live attenuated doses: as per included trials vs placebo, no intervention or control vaccine	0.09 (0.05–0.17) RR of clinically apparent hepatitis A	meta-analysis 9 randomised trials (inactivated and live attenuated)	Irving et al. 2012 Cochrane Database Syst Rev quote In all nine randomised trials, clinically apparent hepatitis A occurred in 31/375,726 (0.01%) versus 505/356,654 (0.18%) participants in the HAV vaccine and control groups respectively (RR 0.09, 95% CI 0.05 to 0.17). abstract, MAIN RESULTS Includes the large Chinese live attenuated trials, most at unclear or high risk of bias. Supported by trial sequential analysis.
Clinically apparent hepatitis A severity: symptomatic case definition: Clinically confirmed hepatitis A as defined in the included trials	children in the included trials country: China (live attenuated trials) n: 690,690 participants 1-4y5-11y12-17y	Live attenuated hepatitis A vaccine (H2 and LA-1 strains) platform: live attenuated doses: 1 vs placebo or no intervention	0.07 (0.03–0.17) RR of clinically apparent hepatitis A	meta-analysis 5 randomised trials of live attenuated vaccine	Irving et al. 2012 Cochrane Database Syst Rev quote Subgroup analyses confirmed the clinical effectiveness of both inactivated hepatitis A vaccines (RR 0.09, 95% CI 0.03 to 0.30) and live attenuated hepatitis A vaccines (RR 0.07, 95% CI 0.03 to 0.17) on clinically confirmed hepatitis A. abstract, MAIN RESULTS Live attenuated vaccine is used in China and India, not in the United States or Europe. The review judged the safety evidence for live vaccine insufficient.
Lack of sero-protective anti-HAV IgG (serological surrogate) severity: serological case definition: Anti-HAV below 20 mIU/L	all ages in the included trials country: multiple All ages	Inactivated hepatitis A vaccine platform: inactivated doses: as per included trials vs placebo, no intervention or control vaccine	0.01 (0.00–0.03) RR of lacking sero-protection	meta-analysis	Irving et al. 2012 Cochrane Database Syst Rev quote Inactivated hepatitis A vaccines had a significant effect on reducing the lack of sero-protection (less than 20 mIU/L) (RR 0.01, 95% CI 0.00 to 0.03). abstract, MAIN RESULTS Serological surrogate, not clinical disease. No trial reported on a threshold below 10 mIU/L.
Hepatitis A cases severity: symptomatic case definition: Cases of hepatitis A as defined in the included trials	adults and children country: multiple All ages	Inactivated hepatitis A vaccine platform: inactivated doses: as per included trials vs placebo or no intervention	86 (63–95) VE (%)	meta-analysis randomised trials with efficacy outcomes	Demicheli et al. 2003 Vaccine quote Combined inactivated vaccine effectiveness was 86% (95% CI: 63-95%). abstract Earlier (2003) review with 8 trials; the authors note poor trial design and reporting. Lower point estimate than the 2012 Cochrane RR 0.09 because of different pooling.
Hepatitis A cases severity: symptomatic case definition: Cases of hepatitis A as defined in the included trials	adults and children country: multiple All ages	Live attenuated hepatitis A vaccine platform: live attenuated doses: as per included trials vs placebo or no intervention	95 (81–99) VE (%)	meta-analysis	Demicheli et al. 2003 Vaccine quote Combined attenuated vaccine effectiveness was 95% (95% CI: 81-99%). abstract Live attenuated vaccine trials are from China and were poorly reported.
Secondary hepatitis A cases (transmission to contacts) severity: symptomatic case definition: Secondary cases among contacts, as defined in the included trials	contacts of cases country: multiple All ages	Inactivated hepatitis A vaccine platform: inactivated doses: as per included trials vs no intervention	82 (23–96) VE (%)	meta-analysis	Demicheli et al. 2003 Vaccine quote Inactivated vaccine effectiveness in the prevention of HAV secondary cases, compared to non-intervention was 82% (95% CI: 23-96%). abstract Wide interval. Measures prevention of onward spread rather than protection of the recipient.
Longest observed persistence of seroprotective anti-HAV severity: serological case definition: Sero-protection by anti-HAV antibodies after more than 5 years of follow-up	all ages in included studies country: multiple All ages	Inactivated and live attenuated hepatitis A vaccines platform: inactivated and live attenuated doses: as per included studies vs none (descriptive review)	15 (live attenuated) and 14 (inactivated) maximum observed persistence of seroprotection (years)	systematic review 13 observational studies	Ott et al. 2012 Vaccine quote The maximum observation times and reported persistence levels of sero-protective anti-HAV antibodies was 15 years for live attenuated HepA and 14 years for inactivated HepA. abstract, RESULTS Reflects the length of available follow-up in 2011, not a limit of protection; later cohorts (Alaska, Belgium, Switzerland) extend this to 20-25 years. Dose and schedule did not significantly affect long-term persistence after inactivated vaccine.
Confirmed breakthrough hepatitis A despite complete vaccination severity: symptomatic case definition: Symptomatic, virologically confirmed hepatitis A at least 50 days after complete vaccination	all ages country: multiple period: publications 1991-2024 n: 43,861 hepatitis A cases reviewed, 832 (partially) vaccinated All ages	Hepatitis A vaccine (any) platform: inactivated and live attenuated doses: complete schedule vs all virologically confirmed hepatitis A cases	6.4 (2.6–14.3) proportion (%) as reported with 95% CI	systematic review 90 reports	Schnyder et al. 2025 Int J Infect Dis quote We identified six confirmed breakthrough infections with proof of complete vaccination (6.4%; 95% confidence interval 2.6-14.3%), including four ICPs (67%). abstract, RESULTS The abstract does not state the denominator for 6.4%; read the full text before using it. Four of the six breakthrough cases (67%) were immunocompromised, versus 17.8% immunocompromised among all confirmed cases, so breakthrough concentrates in people who fail to seroconvert.
Persistence of anti-HAV after inactivated vaccine severity: serological case definition: Detectable anti-HAV antibody	adults vaccinated as children (3-dose) or as adults (2-dose) country: United States 18-49y50-64y	Inactivated hepatitis A vaccine (Havrix or Vaqta) platform: inactivated doses: 3 (children, pre-1999 schedule) or 2 (adults) vs none (expert summary)	at least 25 (3-dose childhood schedule) and at least 20 (2-dose adult schedule) minimum demonstrated persistence of anti-HAV (years)	expert body	cdc.gov quote Anti-HAV has been shown to persist for at least 25 years in adults administered inactivated vaccine as children with the 3-dose schedule recommended prior to 1999, and anti-HAV persistence of at least 20 years also was demonstrated among persons vaccinated with a 2-dose schedule as adults. Immunogenicity and Vaccine Efficacy section The Pink Book states the exact duration of protection is unknown; modelling suggests 40 years or more. No booster is currently recommended.
Protective antibody within 4 weeks of a single dose in adults severity: serological case definition: Protective anti-HAV antibody	adults country: United States 18-49y50-64y65+	Inactivated hepatitis A vaccine (Havrix or Vaqta) platform: inactivated doses: 1 time since vaccination: 4 weeks vs none (expert summary)	more than 95 proportion with protective antibody (%)	expert body	cdc.gov quote More than 95% of adults will develop protective antibody within 4 weeks of a single dose of either vaccine, and nearly 100% will seroconvert after receiving 2 doses. Immunogenicity and Vaccine Efficacy section Basis for the ACIP position that one dose protects most travellers departing within a month; nearly 100% seroconvert after 2 doses.
Clinically apparent hepatitis A severity: symptomatic case definition: Typical signs and symptoms plus diagnostic rise in IgM anti-HAV and ALT at least twice the upper limit of normal, from day 50 after injection	2 to 16 years risk group: seronegative children in a community with recurrent outbreaks country: United States (Monroe, New York) setting: community outbreak period: summer outbreak, published 1992 n: 1037 children (519 vaccine, 518 placebo) 1-4y5-11y12-17y	Formalin-inactivated hepatitis A vaccine (VAQTA) platform: inactivated doses: 1 vs placebo	100 VE (%) follow-up: mean 103 days	RCT	Werzberger et al. 1992 N Engl J Med quote From day 50 after the injection, 25 cases of clinically apparent hepatitis A occurred in the placebo group and none in the vaccine group (P less than 0.001), confirming that the vaccine had 100 percent protective efficacy. abstract, RESULTS 25 cases in placebo versus none in vaccine recipients from day 50. Before day 21 there were 7 cases in the vaccine group and 3 in placebo, so protection is not immediate. Short follow-up.
Clinical hepatitis A severity: symptomatic case definition: Symptoms, ALT 45 U/L or higher and IgM anti-HAV, identified through school absences of 2 or more days	1 to 16 years risk group: schoolchildren in communities with high HAV incidence country: Thailand setting: community (148 primary schools) period: 1991-1993 n: 40,119 children enrolled, 38,157 under surveillance 1-4y5-11y12-17y	Inactivated hepatitis A vaccine (Havrix) platform: inactivated doses: 2 schedule: months 0 and 1 time since vaccination: days 138 through 386 after dose 1 vs hepatitis B vaccine (control vaccine)	94 (79–99) VE (%) follow-up: days 138-386	RCT	Innis et al. 1994 JAMA quote Following two doses of hepatitis A vaccine (days 138 through 386), protective efficacy was 94% (95% confidence interval, 79% to 99%); cumulative efficacy including the postbooster period (days 138 to 532) was 95% (95% confidence interval, 82% to 99%). abstract, RESULTS Control vaccine rather than placebo. Surveillance began a mean of 138 days after dose 1, so early cases are excluded. The two vaccinated cases had mild, brief illness.
Clinical hepatitis A severity: symptomatic case definition: Symptoms, ALT 45 U/L or higher and IgM anti-HAV	1 to 16 years risk group: schoolchildren in communities with high HAV incidence country: Thailand setting: community (148 primary schools) period: 1991-1993 n: 33,586 completing the controlled trial 1-4y5-11y12-17y	Inactivated hepatitis A vaccine (Havrix) platform: inactivated doses: 3 schedule: months 0, 1 and 12 time since vaccination: days 138 through 532 after dose 1 vs hepatitis B vaccine (control vaccine)	95 (82–99) VE (%) follow-up: days 138-532	RCT	Innis et al. 1994 JAMA quote Following two doses of hepatitis A vaccine (days 138 through 386), protective efficacy was 94% (95% confidence interval, 79% to 99%); cumulative efficacy including the postbooster period (days 138 to 532) was 95% (95% confidence interval, 82% to 99%). abstract, RESULTS Includes the period after the 12-month booster; all six post-booster cases were in controls.
Laboratory-confirmed symptomatic hepatitis A 15 to 56 days after exposure severity: symptomatic case definition: Symptomatic infection with laboratory confirmation among susceptible household and day-care contacts	2 to 40 years, average 12 years risk group: susceptible household and day-care contacts of hepatitis A patients prior infection: seronegative (susceptible) at enrolment country: Kazakhstan setting: household contact period: published 2007 n: 1090 per-protocol contacts (568 vaccine, 522 immune globulin) 1-4y5-11y12-17y18-49y	Inactivated hepatitis A vaccine (age-appropriate standard dose) platform: inactivated doses: 1 time since vaccination: given within 14 days of exposure (average 10 days) vs immune globulin	1.35 (0.70–2.67) RR of symptomatic hepatitis A, vaccine vs immune globulin follow-up: 15 to 56 days after exposure	RCT	Victor et al. 2007 N Engl J Med quote Symptomatic infection with hepatitis A virus was confirmed in 25 contacts receiving vaccine (4.4%) and in 17 contacts receiving immune globulin (3.3%) (relative risk, 1.35; 95% confidence interval, 0.70 to 2.67). abstract, RESULTS Non-inferiority criterion met, but the authors note the slightly higher rate with vaccine may reflect a modest true difference. No placebo arm, so absolute efficacy of either is not measured here.
Laboratory-confirmed symptomatic hepatitis A after post-exposure vaccination severity: symptomatic case definition: Symptomatic infection with laboratory confirmation among susceptible contacts	2 to 40 years, average 12 years risk group: susceptible household and day-care contacts prior infection: seronegative at enrolment country: Kazakhstan setting: household contact n: 568 vaccine recipients 1-4y5-11y12-17y18-49y	Inactivated hepatitis A vaccine platform: inactivated doses: 1 time since vaccination: within 14 days of exposure vs immune globulin (attack rate 3.3%)	4.4 attack rate among vaccine recipients (%) follow-up: 15 to 56 days after exposure	RCT	Victor et al. 2007 N Engl J Med quote Symptomatic infection with hepatitis A virus was confirmed in 25 contacts receiving vaccine (4.4%) and in 17 contacts receiving immune globulin (3.3%) (relative risk, 1.35; 95% confidence interval, 0.70 to 2.67). abstract, RESULTS Absolute attack rates for both arms are in the same sentence. Most prophylaxis was given in the second week after exposure.
Protective anti-HAV (20 mIU/mL or more) 20 years after childhood vaccination severity: serological case definition: Anti-HAV at or above 20 mIU/mL	vaccinated at 3-6 years, measured 20 years later risk group: Alaska Native children country: United States (Alaska) n: 52 of 144 original participants 18-49y	Inactivated hepatitis A vaccine (360 ELISA units per dose) platform: inactivated doses: 3 schedule: 0,1,2 or 0,1,6 or 0,1,12 months time since vaccination: 20 years vs none (randomisation was between schedules)	88.5 proportion with protective antibody (%) follow-up: 20 years	RCT	Plumb et al. 2017 J Viral Hepat quote Overall, 46 (88.5%) of 52 available participants had anti-HAV antibody concentrations ≥20 mIU mL-1 , and overall GMC was 107 mIU mL-1 . abstract Only 36% of the cohort was available at 20 years. Lower antibody in the 0,1,2-month group was explained by a lower initial peak. Threshold is 20 mIU/mL, stricter than the 10 mIU/mL used in Argentine studies.
Loss of seroprotection 10 years after infant vaccination at 6 and 12 months severity: serological case definition: Anti-HAV above 10 mIU/mL	vaccinated at 6 and 12 months, measured at 10 years country: United States n: 197 children randomised across 3 schedules 5-11y	Inactivated hepatitis A vaccine platform: inactivated doses: 2 schedule: 6 and 12 months of age time since vaccination: 10 years vs children vaccinated at 12 and 18 or 15 and 21 months (all retained seroprotection except 4% of one subgroup)	7 (anti-HAV-negative mothers) and 11 (anti-HAV-positive mothers) proportion losing seroprotection by 10 years (%) follow-up: 10 years	RCT	Sharapov et al. 2012 Hepatology quote At 10 years, all children retained seroprotective anti-HAV levels except for only 7% and 11% of children in group 1 born to anti-HAV-negative and anti-HAV-positive mothers, respectively, and 4% of group 3 children born to anti-HAV-negative mothers. abstract The earliest schedule and maternal antibody both lowered persistence, which is why routine vaccination starts at 12 months. Antibody levels through 10 years tracked the initial peak response.
Seropositivity for anti-HAV 20 years after 2-dose adult vaccination severity: serological case definition: Seropositive anti-HAV antibodies	adults vaccinated in 1992-1993 country: Belgium n: 34/36 and 85/86 according-to-protocol subjects 18-49y50-64y	Inactivated hepatitis A vaccine (Havrix 1440 El.U) platform: inactivated doses: 2 schedule: 0-6 or 0-12 months time since vaccination: 20 years vs none (randomisation was between schedules)	more than 97 proportion seropositive (%) follow-up: 20 years	RCT	Theeten et al. 2015 Vaccine quote After 20 years, >97% of the subjects in both studies were seropositive for anti-HAV antibodies. abstract Small cohorts. Modelling predicted at least 95% seropositive at 30 years and at least 90% at 40 years. Seven subjects who lost antibody responded strongly to a booster.
Seroconversion after 2 doses in HIV-infected adults severity: serological case definition: Anti-HAV seroconversion at week 28	adults immune status: HIV-infected (stratified by CD4 count) country: United States n: 90 HIV-infected randomised, 90 HIV-uninfected 18-49y50-64y	Inactivated hepatitis A vaccine (VAQTA) platform: inactivated doses: 2 schedule: weeks 0 and 24 vs HIV-uninfected adults (100%); placebo arm among HIV-infected	94 seroconversion (%)	RCT	Wallace et al. 2004 Clin Infect Dis quote Seroconversion rates at week 28 of the study were 94% among the HIV-infected subjects and 100% among the HIV-uninfected control subjects. abstract, RESULTS Seroconversion was 87% with CD4 below 300 and 100% with CD4 300 or above (hepatitis-a-eff-033). Immunogenicity, not clinical protection.
Seroconversion after 2 doses in HIV-infected adults with low CD4 count severity: serological case definition: Anti-HAV seroconversion at week 28	adults immune status: HIV-infected with CD4 below 300 cells/mm3 country: United States n: 45 subjects with CD4 below 300 18-49y50-64y	Inactivated hepatitis A vaccine (VAQTA) platform: inactivated doses: 2 schedule: weeks 0 and 24 vs HIV-infected with CD4 300 or above (100%)	87 seroconversion (%)	RCT	Wallace et al. 2004 Clin Infect Dis quote HIV-infected subjects with CD4 cell counts of <300 cells/mm3 had a seroconversion rate of 87%, and HIV-infected subjects with CD4 cell counts of > or =300 cells/mm3 had a seroconversion rate of 100%. abstract, RESULTS Reduced response with advanced immunosuppression; post-vaccination serology is advised in this group.
Seroprotection (anti-HAV IgG 10 mIU/mL or more) 4 years after a single dose severity: serological case definition: IgG anti-HAV at or above 10 mIU/mL	5-year-old children vaccinated at 1 year country: Argentina period: published 2015 n: 1139 children 5-11y	Inactivated hepatitis A vaccine platform: inactivated doses: 1 schedule: single dose at 12 months time since vaccination: 4 years vs none (single-arm seroprevalence; seroprotection threshold)	93 (91.7–94.6) proportion seroprotected (%) follow-up: 4 years	cohort	Vizzotti et al. 2015 J Pediatric Infect Dis Soc quote From 1139 in Group B, 93% (95% CI, 91.7-94.6) maintained seroprotection with a GMC of 97.96 mIU/mL (95% CI, 89.21-107.57 mIU/mL). abstract, RESULTS Antibody level is a surrogate; clinical protection may persist after antibody wanes (see hepatitis-a-eff-021). Residual viral circulation may boost some children.
Seroprotection (anti-HAV 10 mIU/mL or more) 6-9 years after a single dose severity: serological case definition: Anti-HAV antibody values at or above 10 mIU/mL	children vaccinated at 1 year, median 7.7 years earlier (range 6.3-9.2) country: Argentina period: 2013-2014 n: 1088 children 5-11y	Inactivated hepatitis A vaccine platform: inactivated doses: 1 schedule: single dose at 12 months time since vaccination: median 7.7 years vs none (single-arm seroprevalence; seroprotection threshold)	97.4 (96.3–98.3) proportion seroprotected (%) follow-up: 6.3-9.2 years	cohort	Urueña et al. 2016 Pediatr Infect Dis J quote Of these children, 97.4% (95% confidence interval: 96.3%-98.3%) had protective antibodies against HAV. abstract, RESULTS Higher than the 4-year figure from the same programme, which suggests natural boosting or cohort differences rather than true antibody rise. Serological surrogate.
Seroprotection (anti-HAV 10 mIU/mL or more) 5 years after one or two doses severity: serological case definition: Anti-HAV at or above 10 mIU/mL	children vaccinated at 11-23 months, followed 5 years country: Argentina (Mendoza) n: 318 one-dose and 85 two-dose children evaluable at year 5 5-11y	Inactivated hepatitis A vaccine (Avaxim 80U Pediatric) platform: inactivated doses: 1 time since vaccination: 5 years vs 2 doses (100% seroprotected)	99.7 proportion seroprotected after one dose (%) follow-up: 5 years	cohort	Espul et al. 2015 J Viral Hepat quote Seroprotection rates were still high in Group 1 (99.7%) and in Group 2 (100%) 5 years after one or two doses of Avaxim 80U Pediatric, correspondingly. abstract Observational, non-randomised dose groups; GMCs were higher after two doses. Serological surrogate.
Anamnestic response to a booster in single-dose recipients who had lost protective antibody severity: serological (immune memory) case definition: Anti-HAV above 10 mIU/mL 30 days after booster	children vaccinated at 1 year, average 12 years of follow-up country: Argentina n: 52 individuals with unprotective antibody levels 12-17y	Inactivated hepatitis A vaccine platform: inactivated doses: 1 (plus study booster) time since vaccination: average 12 years vs none (single arm)	92 proportion reaching protective levels after booster (%) follow-up: 12 years	cohort	Urueña et al. 2022 Vaccine quote The results showed that 48/52 (92%) individuals from UAL group who completed follow up reached protective levels after booster dose. abstract Evidence of immune memory despite waned antibody, supporting single-dose policy; HAV-specific memory T cells were found regardless of antibody level. Not a measure of clinical protection.
Protective anti-HAV (20 mIU/mL or more) 25 years after childhood vaccination severity: serological case definition: Anti-HAV IgG at or above 20 mIU/mL	vaccinated in early childhood, measured 25 years later risk group: Alaska Native individuals country: United States (Alaska) n: 43 of 144 original participants 18-49y	Inactivated hepatitis A vaccine platform: inactivated doses: 3 time since vaccination: 25 years vs none (single cohort)	81.4 proportion with protective antibody (%) follow-up: 25 years	cohort	Ramaswamy et al. 2021 J Med Virol quote At 25 years, 43 of the original 144 participants were available, mean anti-HAV levels were 91.5 mIU/mL, and 35 (81.4%) had protective levels of anti-HAV. abstract Survival analysis using all time points estimated 78.7% protected at 25 years. Heavy loss to follow-up. Serological surrogate.
Seropositivity (20 mIU/mL or more) 20 years after infant vaccination severity: serological case definition: Anti-HAV at or above 20 mIU/mL	vaccinated as infants, measured 20 years later country: United States (Alaska) n: 75 of 183 original participants 18-49y	Inactivated hepatitis A vaccine platform: inactivated doses: 2 schedule: one of three infant schedules time since vaccination: 20 years vs none (single cohort)	68 proportion seropositive (%) follow-up: 20 years	cohort	Mosites et al. 2020 Vaccine quote The overall anti-HAV geometric mean concentration was 29.9 mIU/mL (95% CI 22.4 mIU/mL, 39.7 mIU/mL) and 50 participants (68%) remained seropositive (titer ≥ 20 mIU/mL). abstract Markedly lower than persistence after vaccination at 3-6 years (hepatitis-a-eff-022), consistent with maternal antibody interference or infant immune immaturity. Model predicted seropositivity below 50% by about 30 years. The authors could not say whether protection persists once antibody is lost.
Seroprotection (10 mIU/mL or more) 20 years after 2-dose adult vaccination severity: serological case definition: Anti-HAV at or above 10 mIU/mL	mean 44.71 years at the 20-year visit country: Switzerland n: 94 18-49y50-64y	Inactivated virosomal hepatitis A vaccine (Epaxal) platform: inactivated (virosomal) doses: 2 schedule: 0 and 12 months time since vaccination: 20 years vs none (single cohort)	100 (96.2–100.0) proportion seroprotected (%) follow-up: 20 years	cohort	Chappuis et al. 2017 Vaccine quote Participants completing 0/12-month Epaxal® immunization regimen (N=94) had seroprotection rate of 100% (95% CI: 96.2, 100.0) with ⩾10mIU/mL seropositivity cut-off and 98.9% (95% CI: 94.2, 100.0) with ⩾20mIU/mL cut-off. abstract, RESULTS Modelled median duration of protection 77.3 years at the 10 mIU/mL cut-off. Epaxal is no longer marketed in many countries.
Hepatitis A cases severity: symptomatic case definition: Reported hepatitis A among primary school children under 4-year surveillance	primary school children country: China (Shaoxing County) setting: community (11 primary schools) period: 1991-1995 5-11y12-17y	Live attenuated hepatitis A vaccine (H2 strain) platform: live attenuated doses: 1 vs unvaccinated control schoolchildren	none among 18102 vaccinated person-years vs 495 among 242168 control person-years cases per cumulative person-years, vaccinated vs control follow-up: 4 years	cohort	Mao et al. 1997 Vaccine quote Since then, there has been no hepatitis A reported among 18102 cumulative person-years in the vaccination group, while 495 cases occurred among 242168 cumulative person-years in the control groups. abstract No VE or interval reported; the cached sentence gives raw counts only. Allocation method is not described in the abstract.
Anti-HAV seropositivity 10 years after live attenuated vaccine severity: serological case definition: Serum anti-HAV by ELISA calibrated to WHO reference	vaccinated at 1-3 years, followed 10 years country: China n: 220 children 5-11y12-17y	Live attenuated hepatitis A vaccine (H2 strain) platform: live attenuated doses: 1 time since vaccination: 10 years (98.6% at 2 months) vs none (single cohort)	80.2 proportion seropositive at 10 years (%) follow-up: 10 years	cohort	Zhuang et al. 2005 Chin Med J (Engl) quote RESULTS: Seroconversion in follow-up assay 2 months and 10 years after inoculation was 98.6% and 80.2% respectively. abstract, RESULTS Lower 10-year seropositivity than inactivated vaccine cohorts, though no clinical cases occurred in cohorts aged 1-15 once coverage reached 85%. Serological surrogate.
Seroconversion at week 48 in HIV-infected men who have sex with men severity: serological case definition: Anti-HAV seroconversion, intention-to-treat	18 to 40 years sex: male risk group: men who have sex with men immune status: HIV-infected prior infection: seronegative for HAV country: Taiwan period: 2009-2010 n: 140 two-dose HIV-infected, 225 three-dose HIV-infected, 217 HIV-uninfected 18-49y	Inactivated hepatitis A vaccine (1,440 ELISA units) platform: inactivated doses: 2 schedule: 0 and week 24 vs HIV-uninfected MSM with 2 doses (88.5%); HIV-infected with 3 doses (77.8%)	75.7 seroconversion (%) follow-up: 48 weeks	cohort	Tseng et al. 2013 Hepatology quote At week 48, the seroconversion rate was 75.7%, 77.8%, and 88.5% in intention-to-treat analysis for two-dose HIV-infected, three-dose HIV-infected, and two-dose HIV-uninfected MSM, respectively. abstract, RESULTS A third dose raised antibody concentration but not seroconversion rate. Higher CD4 count and undetectable viral load predicted seroconversion.
Seroconversion one year after a single dose in people living with HIV severity: serological case definition: Anti-HAV seropositivity at one year	adults, age-matched groups immune status: people living with HIV country: Taiwan period: February 2016-December 2017 n: 90 single-dose cases and 90 two-dose controls 18-49y50-64y	Inactivated hepatitis A vaccine platform: inactivated doses: 1 time since vaccination: 1 year vs people living with HIV who received 2 doses (97.78%)	56.67 seroconversion after one dose (%) follow-up: 1 year	case-control	Tsai et al. 2022 J Microbiol Immunol Infect quote Seroconversion rate at one year was significantly higher in 2 doses group (97.78% vs 56.67%, p < 0.0001). abstract, RESULTS The single-dose group had more injection drug use and hepatitis C co-infection, which were associated with non-response; confounding by indication is likely. The single-dose strategy that works in healthy toddlers does not transfer to this group.
Anti-HAV seropositivity after a full course in HIV-positive patients severity: serological case definition: Anti-HAV antibodies detected after full vaccination course	adults immune status: HIV-positive country: Germany 18-49y50-64y	Hepatitis A monovalent vaccine or hepatitis A/B combined vaccine (Twinrix) platform: inactivated doses: full course vs none (single-arm; mono vs combined vaccine compared within study)	80.2 proportion seropositive (%)	cohort	Fritzsche et al. 2019 Vaccine quote RESULTS: After vaccination, 80.2% of the patients developed anti-HAV antibodies, 81.5% in the mono-vaccine group and 79.2% in the hepatitis A/B co-vaccine group. abstract, RESULTS Retrospective cross-sectional serology at variable intervals after vaccination; a longer interval (over 5 years) was associated with lower seropositivity, so this mixes non-response with waning.
Seropositivity 15 days after the first dose in adults aged 40 or older severity: serological case definition: Anti-HAV seropositivity 15 days after dose 1	40 years or older (control group 20-30 years) country: multiple (pooled trials) n: 80 per group 18-49y50-64y65+	Inactivated hepatitis A vaccine (Havrix) platform: inactivated doses: 1 time since vaccination: 15 days vs adults aged 20-30 years (92.3%)	79.7 (68.8–88.2) proportion seropositive (%)	cohort 4 two-dose primary vaccination studies	Van et al. 2015 Hum Vaccin Immunother quote Fifteen days after the first vaccine dose, 79.7% (95% CI: 68.8-88.2) and 92.3% (95% CI: 84.0-97.1) of subjects were seropositive in the ≥ 40 years and control groups, respectively; 97.5% (95% CI: 91.2-99.7) and 97.4% (95% CI: 91.0-99.7), respectively, were seropositive one month after the first dose. abstract Slower early response in older adults, but 97.5% were seropositive one month after dose 1 and 100% after dose 2 in both age groups. Relevant to last-minute travel vaccination.
Reported HAV infection, all ages severity: any reported case case definition: HAV infections reported to the National Epidemiological Surveillance System	all ages country: Argentina setting: national surveillance period: 2006-2011 versus 2000-2002 All ages	Inactivated hepatitis A vaccine platform: inactivated doses: 1 schedule: single dose at 12 months of age vs pre-vaccination period (2000-2002)	88.1 relative reduction in reported incidence (%)	ecological	Vizzotti et al. 2014 Pediatr Infect Dis J quote The mean incidence rate of 7.9/100,000 in the postvaccination period represents a reduction of 88.1% (P < 0.001) when compared with the prevaccination period. abstract, RESULTS Population-level impact of a one-dose schedule, including herd effects in unvaccinated age groups; not an individual VE. Fulminant hepatic failure and transplantation due to HAV were not observed after March 2007.
Reported hepatitis A disease in the vaccinated cohort severity: any reported case case definition: Hepatitis A reported to SINAVE national surveillance	children aged 1 year country: Argentina setting: national surveillance period: 2007 versus 1998-2002 1-4y	Inactivated hepatitis A vaccine platform: inactivated doses: 1 schedule: single dose at 12 months of age vs pre-vaccination baseline (1998-2002)	83.1 relative reduction in reported incidence (%)	ecological	Vacchino 2008 J Viral Hepat quote For children aged 1 year, an 83.1% reduction in disease was observed in 2007, compared with the baseline period (P < 0.001). abstract Coverage was 95% in 2006. The one-year-olds are the directly vaccinated cohort; older age groups in the same sentence show herd effects.
Reported hepatitis A disease in unvaccinated adults over 50 (herd effect) severity: any reported case case definition: Hepatitis A reported to SINAVE national surveillance	over 50 years country: Argentina setting: national surveillance period: 2007 versus 1998-2002 50-64y65+	Inactivated hepatitis A vaccine (given to 12-month-olds only) platform: inactivated doses: 1 schedule: single dose at 12 months of age vs pre-vaccination baseline (1998-2002)	20.7 relative reduction in reported incidence (%)	ecological	Vacchino 2008 J Viral Hepat quote Furthermore, a sharp decline was also observed in all other age groups 87.1% [2-4 years], 88.7% [5-9 years], 83.6% [10-14 years], 78.8% [15-49 years], 20.7% [>50 years]. abstract Indirect (herd) effect in an unvaccinated age group; by far the smallest decline of any age band, versus 87.1% in 2-4 year olds. Toddler vaccination protects older adults least.
Reported hepatitis A disease in the vaccinated age group severity: any reported case case definition: Hepatitis A cases reported to national passive surveillance, validated by active surveillance in Jerusalem	1 through 4 years country: Israel setting: national surveillance period: 2002-2004 versus 1993-1998 1-4y	Inactivated hepatitis A vaccine platform: inactivated doses: 2 schedule: 18 and 24 months of age, no catch-up vs pre-vaccination period (1993-1998)	98.2 relative reduction in reported incidence (%)	ecological	Dagan et al. 2005 JAMA quote For children aged 1 through 4 years, a 98.2% reduction in disease was observed in 2002-2004, compared with the prevaccination period (P<.001). abstract, RESULTS Coverage 90% first dose and 85% second dose. Pre-vaccination incidence was 50.4 per 100,000.
Reported hepatitis A disease in unvaccinated older adults (herd effect) severity: any reported case case definition: Hepatitis A cases reported to national passive surveillance	65 years or older country: Israel setting: national surveillance period: 2002-2004 versus 1993-1998 65+	Inactivated hepatitis A vaccine (given to toddlers only) platform: inactivated doses: 2 schedule: 18 and 24 months of age vs pre-vaccination period (1993-1998)	77.3 relative reduction in reported incidence (%)	ecological	Dagan et al. 2005 JAMA quote However, a sharp decline was also observed in all other age groups (84.3% [<1 year], 96.5% [5-9 years], 95.2% [10-14 years], 91.3% [15-44 years], 90.6% [45-64 years], and 77.3% [>or=65 years]). abstract, RESULTS Indirect effect in an age group that received no vaccine; the smallest reduction of all age bands in the same sentence.

Gaps

No controlled safety record is compiled: the Cochrane review (PMID 22786522) states non-serious adverse events were comparable to placebo for inactivated vaccine but gives no number in the abstract, and a search for SCCS or cohort studies of hepatitis A vaccine adverse events returned nothing specific to this vaccine.
No WHO position paper record: the 2022 position paper is a PDF behind the WHO landing page and only the landing page text was captured, so WHO's pooled long-term effectiveness statements are not compiled.
No case-fatality or fulminant-hepatitis rate specific to people with chronic liver disease was found as a number: the Pink Book and the Lefilliatre review state the risk is increased without quantifying it, and the outbreak case-control (hepatitis-a-bur-035) gives an odds ratio for death among cases, not an absolute risk.
No age-specific symptomatic attack rate study was found beyond the Pink Book summary (70% asymptomatic under 6 years; jaundice in more than 70% of older children and adults); the primary seroepidemiological sources behind those figures were not identified.
No clinical (case-based) vaccine effectiveness estimate was found for adult travellers, for people experiencing homelessness or for people who use drugs; the outbreak literature reports vaccination status of cases and vaccine doses delivered, not VE.
No clinical waning record: every long-term record (hepatitis-a-eff-018 to -029, -031) is an antibody persistence figure. No cohort has counted breakthrough disease over 10-25 years against an unvaccinated comparator, and the Argentine single-dose evidence of durable clinical protection is ecological (incidence trends) plus serology.
No post-exposure prophylaxis record against placebo or no treatment for vaccine: the only RCT (hepatitis-a-eff-011) compares vaccine with immune globulin; the Cochrane immunoglobulin review (PMID 19370595) was listed but not compiled.
No pregnancy record: hepatitis A vaccine in pregnancy (Groom 2019 Vaccine Safety Datalink study cited by the Pink Book) was not searched for or compiled.
No LMIC burden record outside Latin America: the Cochrane and Chinese live-attenuated sources give efficacy, not disease burden, for high-endemicity settings; no sub-Saharan Africa or South Asia burden figure was compiled.
No ICU admission proportion was found for hepatitis A; hospitalisation and death are the only severity tiers compiled.
No safety record (see the first GAP line); the Pink Book's statements that the vaccine is well tolerated carry no comparative number.

Flags for review

hepatitis-a-bur-001, -002, -004, -005, -018 and hepatitis-a-pa-001 are CDC Pink Book summary figures (expert body) without primary citations in the cached text and without intervals. They are the only sources here for the all-ages CFR, the older-adult CFR and the age-symptom gradient; a reviewer should decide whether expert-body numbers may stand alone on the page.
Hospitalisation proportions differ by source and period: 7.3% of reported cases in 1999 and 24.5% in 2011 (hepatitis-a-bur-024), 51.8% in a random sample of 2016-2019 outbreak cases (hepatitis-a-bur-033), 61-71% in aggregate outbreak reporting (hepatitis-a-bur-028, -030, -032). The aggregate outbreak figures likely include admissions driven by housing status and reporting bias, not only severity. Do not present a single hospitalisation risk.
Case-fatality ranges from 0.02% (Italy 1985-1994, hepatitis-a-bur-006) to 3% (2017 US outbreaks among people experiencing homelessness and people who use drugs, hepatitis-a-bur-029) and 14% among adults with HAV acute liver failure (hepatitis-a-bur-010). These have different denominators (all reported cases, outbreak cases, acute liver failure cases) and must not be placed side by side without the denominator labelled.
hepatitis-a-bur-014 (fulminant hepatic failure in 0.4% of paediatric cases) is a literature figure quoted in the introduction of Cervio 2011, not a measurement from that study. The primary source is not identified in the abstract.
hepatitis-a-bur-017 (HAV causes 10% of paediatric liver transplants in France and 20% in Argentina) comes from a narrative review abstract without a cited source; treat as illustrative.
Nearly all long-term efficacy records are serological surrogates (anti-HAV above 10 or 20 mIU/mL). Thresholds differ between studies (10 mIU/mL in Argentina and Switzerland, 20 mIU/mL in Alaska and Cochrane), so persistence percentages are not directly comparable. The Argentine 12-year memory study (hepatitis-a-eff-021) suggests clinical protection outlasts detectable antibody, so a low seropositivity figure (for example 68% at 20 years after infant vaccination, hepatitis-a-eff-024) should not be read as 32% unprotected.
hepatitis-a-eff-004 to -007 are Cochrane risk ratios (RR 0.09 means roughly 91% fewer cases), while hepatitis-a-eff-002, -003, -008 to -010 are VE percentages. They are left on their native scales as the rules require; the page must label the scale so readers do not read 0.09 as 9% efficacy.
hepatitis-a-eff-011 (post-exposure vaccine vs immune globulin, RR 1.35, CI 0.70-2.67) met non-inferiority but the point estimate favours immune globulin. The authors themselves say a modest true difference may be clinically meaningful in some settings. Present both the RR and the absolute attack rates (4.4% vs 3.3%, hepatitis-a-eff-012).
hepatitis-a-eff-013 to -017 are ecological before-after reductions from national surveillance (Argentina, Israel), not individual VE; they include herd effects and secular trends. The small reductions in the oldest unvaccinated groups (20.7% over 50 in Argentina, hepatitis-a-eff-015) show that toddler programmes leave older adults exposed.
hepatitis-a-eff-038 (6.4% confirmed breakthrough, CI 2.6-14.3): the abstract does not say what the denominator of 6.4% is. Full text must be checked before this number is displayed.
PMID 16143420 (Spada 2005, Italian outbreak among injecting drug users) reports three deaths among 47 symptomatic cases, mostly in people with cirrhosis, but writes 'Three' in words so the compiler cannot verify a numeric CFR; the finding is relevant to the chronic liver disease risk group and could be added if the full text is snapshotted.
The disease is marked notifiable on the strength of the Pink Book statement that hepatitis A became nationally notifiable in the United States in 1966; notifiability differs in other countries used here (Argentina, Israel, Taiwan, Italy all have national surveillance per the cited abstracts).

Search log (45 searches)

hepatitis A vaccine efficacy randomized Monroe children · PubMed → Found PMID 1320740 (Werzberger 1992 Monroe trial); compiled as hepatitis-a-eff-001.
hepatitis A vaccine efficacy Thailand randomized trial · PubMed → Found PMID 8158817 (Innis 1994 Thailand RCT); compiled as hepatitis-a-eff-002 and -003.
hepatitis A mortality case-fatality age surveillance · PubMed → Found PMID 33217769 (outbreak mortality case-control), 27386835 (Taiwan hospitalised cohort), 9112305 (Italy surveillance CFR); compiled as burden records.
hepatitis A case fatality fulminant hepatitis age United States surveillance · PubMed → No hits with this wording; re-run with broader terms (next line).
hepatitis A outbreaks homelessness drug use hospitalization United States 2016 · PubMed → Found PMIDs 36173747 (MMWR 2016-2020), 41578878 (37 states 2016-2023), 33097935 (KY/MI/WV sample); compiled as hepatitis-a-bur-030 to -034.
hepatitis A single dose vaccination Argentina universal programme effectiveness · PubMed → Only an editorial (PMID 18837828); re-run as 'single-dose hepatitis A vaccine Argentina'.
single-dose hepatitis A vaccine Argentina · PubMed → Found PMIDs 24352191, 18837834 (programme impact), 26582885, 27636725, 25262590, 28933624, 34838323 (antibody persistence); compiled as hepatitis-a-eff-013 to -015 and -018 to -021.
hepatitis A vaccine Alaska long-term persistence antibody follow-up · PubMed → No hits with this wording; found via the antibody-persistence search below.
hepatitis A vaccine versus immune globulin postexposure prophylaxis randomized · PubMed → Found PMID 17947390 (Victor 2007 NEJM) and Cochrane immunoglobulin review 19370595 (not used); compiled as hepatitis-a-eff-011 and -012.
vaccines for preventing hepatitis A Cochrane systematic review · PubMed → Found PMID 22786522 (Irving 2012 Cochrane), 12744850 (Demicheli 2003), 27786671 (Stuurman 2017 UMV impact review); compiled as hepatitis-a-eff-004 to -010.
hepatitis A chronic liver disease superinfection fulminant hepatic failure mortality · PubMed → Found PMID 10927841 (case reports plus narrative review, no usable number) and hepatitis E papers; no quantitative CFR for HAV superinfection in CLD found (see GAP).
hepatitis A vaccine travelers effectiveness incidence · PubMed → Found PMID 35134210 (GeoSentinel 2008-2020); compiled as hepatitis-a-bur-037 and -038. No traveller VE estimate found.
hepatitis A vaccine antibody persistence 20 years adults · PubMed → Found PMIDs 28092416 (Alaska 20 y), 26190091 (Havrix 20 y), 28190741 (Epaxal 20 y), 22371069 (infants 10 y), 22609026 (Ott review); compiled as hepatitis-a-eff-022, -025 to -028.
hepatitis A incidence United States decline vaccination recommendations surveillance · PubMed → Found PMIDs 16014593 (Wasley 2005), 18422440 (Vogt 2008 mortality), 31071072 (MMWR 2013-2018), 37480244 (Hofmeister 2023 trends); compiled as hepatitis-a-bur-019 to -022, -026, -027.
hepatitis A symptomatic infection proportion children adults jaundice age · PubMed → Only an Indian policy paper (22854671); symptomatic proportion taken from the CDC Pink Book instead (hepatitis-a-bur-004, -005).
WHO position paper hepatitis A vaccines 2022 · PubMed → No PubMed record; the WHO landing page was snapshotted (web_id who-int-6351fadb1d) but holds only the overview, not the PDF text (see FLAG).
hepatitis A hospitalization rate cases United States surveillance 2000s · PubMed → No hits with this wording; US hospitalisation found via title searches for Collier 2015 and Ly 2015 (below).
hepatitis A vaccine effectiveness children long-term Israel universal toddler · PubMed → Only a review (29661808); re-run as Israel toddler programme search (below).
hepatitis A toddler vaccination program Israel incidence decline · PubMed → Found PMID 16014594 (Dagan 2005 JAMA); compiled as hepatitis-a-eff-016, -017 and hepatitis-a-bur-039.
live attenuated hepatitis A vaccine H2 efficacy China children · PubMed → Found PMIDs 9261939 (Mao 1997), 16313838 (Zhuang 2005) and several Chinese-language papers; compiled as hepatitis-a-eff-030 and -031.
hepatitis A vaccine HIV seroconversion immunogenicity meta-analysis · PubMed → No hits with this wording; re-run below.
hepatitis A vaccination HIV-infected seroconversion rate · PubMed → Found PMIDs 15486846 (Wallace 2004 RCT), 23258666 (Tseng 2013), 30890384 (Fritzsche 2019); compiled as hepatitis-a-eff-032 to -034, -036.
hepatitis A outbreak San Diego 2017 hospitalization deaths homeless · PubMed → No hits with this wording (San Diego papers surfaced in the homelessness search but were not needed beyond the CDC aggregate data).
hepatitis A relapsing prolonged cholestatic hepatitis proportion cases · PubMed → No hits; relapsing-hepatitis proportion taken from the Pink Book (hepatitis-a-pa-001).
acute liver failure hepatitis A etiology registry proportion transplant · PubMed → No hits with this wording; found via the paediatric ALF search below.
hepatitis A vaccine older adults immunogenicity seroconversion age 40 · PubMed → Found PMID 26029816 (Havrix pooled analysis, 40 years or older); compiled as hepatitis-a-eff-037.
hepatitis A acute liver failure children etiology Argentina transplantation · PubMed → Found PMIDs 17848883 (Latin America ALF), 24367225 (Cervio FHF decline), 10683554 (Ciocca review), 31606931 (not used); compiled as hepatitis-a-bur-012 to -017.
hepatitis A outbreak Michigan 2016 2018 deaths hospitalized · PubMed → No hits with this wording.
hepatitis A seroprevalence clinical attack rate age dependent severity · PubMed → Only a Thai seroprevalence paper (12125918); no age-specific symptomatic attack rate study found (see GAP).
hepatitis A vaccine effectiveness case-control outbreak · PubMed → Found PMID 32690395 (one vs two doses in PLHIV, Taiwan); compiled as hepatitis-a-eff-035. No outbreak VE case-control study of healthy populations found.
Fulminant hepatitis A virus infection in the United States incidence prognosis outcomes Acute Liver Failure Study Group · PubMed → No hits with this wording; found as PMID 17133489 by re-running without the group name; compiled as hepatitis-a-bur-010 and -011.
Hepatitis A hospitalizations in the United States 2002-2011 · PubMed → Found PMID 25266085 (Collier 2015); compiled as hepatitis-a-bur-025.
outbreak hepatitis A high case-fatality rate injecting drug users Italy · PubMed → Found PMID 16143420 (Spada 2005); deaths are written as 'Three' in the abstract so no numeric record could be compiled (see FLAG).
Hepatitis A vaccine immunogenicity 25 years after vaccination Alaska · PubMed → Found PMIDs 33448443 (Ramaswamy 2021), 32535018 (Mosites 2020 infants); compiled as hepatitis-a-eff-023 and -024.
trends in hepatitis A mortality United States Ly Klevens · PubMed → Found PMID 25637352 (Ly 2015); compiled as hepatitis-a-bur-023 and -024.
Progress toward eliminating hepatitis A disease in the United States · PubMed → Found PMID 26916458 (Murphy 2016); abstract carries no number, not compiled.
hepatitis A single dose inactivated vaccine effectiveness systematic review meta-analysis long-term · PubMed → No hits.
fulminant hepatitis A United States acute liver failure incidence prognosis · PubMed → Found PMID 17133489 (Taylor 2006 ALFSG); compiled as hepatitis-a-bur-010 and -011.
hepatitis A vaccine safety Vaccine Safety Datalink controlled adverse events · PubMed → No hits.
hepatitis A prolonged cholestasis relapse extrahepatic manifestations cohort · PubMed → No hits.
hepatitis A vaccine self-controlled case series OR cohort adverse events Guillain-Barre anaphylaxis · PubMed → Only COVID-19, pneumococcal and HPV vaccine safety papers; nothing on hepatitis A vaccine.
hepatitis A infection long-term sequelae follow-up after acute hepatitis A · PubMed → No relevant hits (autoimmune hepatitis and transplant papers only).
hepatitis A hospitalization Kentucky outbreak 2017 2018 case fatality · PubMed → No hits.
https://www.cdc.gov/pinkbook/hcp/table-of-contents/chapter-9-hepatitis-a.html · websource → Snapshotted as cdc-gov-5a8172d16d (Pink Book chapter 9, 14th edition); used for CFR, symptomatic proportion, pre-vaccine incidence, 2017 outbreak and persistence records.
https://www.who.int/publications/i/item/who-wer9740-493-512 · websource → Snapshotted as who-int-6351fadb1d; landing page only, the position paper PDF text was not captured.