Evidence
Vaccine safety studies: what controlled research found
154 results from studies with a comparison group or control period — 70 found an increased risk of a specific outcome (with excess cases per million doses where reported), 74 found no increased risk. Passive-reporting rates are labelled separately.
Every number was taken from the study abstract, the FDA/CDC page or the IOM 2011 report summary tables and is linked to its source. Where an abstract gave no confidence interval, none is shown. Gaps (for example typhoid, rabies and cholera vaccines) are listed in the data file.
Influenza vaccines
| Outcome | Design & population | Estimate (95% CI) | Excess per million doses | Finding | Source |
|---|---|---|---|---|---|
Anaphylaxis Trivalent inactivated influenza (given alone) | cohort with chart review (VSD) Children and adults, US (7,434,628 doses) | incidence per million doses 1.35 (0.65–2.47) | — | increased risk | McNeil MM et al., 2016, J Allergy Clin Immunol doi:10.1016/j.jaci.2015.07.048; PMID 26452420 |
Any medically attended event (screen of all diagnoses) Trivalent inactivated influenza (TIV) | self-controlled (VSD) with chart review Children 6-23 mo, US 1991-2003 (45,356 children; 69,359 vaccinations) | — | — | no increased risk detected | Hambidge SJ et al., 2006, JAMA doi:10.1001/jama.296.16.1990; PMID 17062862 |
Asthma exacerbation / reactive airway disease Inactivated influenza | expert causality review (IOM 2011) Children and adults | — | — | no increased risk detected | Institute of Medicine (Stratton K et al., eds.), 2011, Adverse Effects of Vaccines: Evidence and Causality, National Academies Press doi:10.17226/13164 |
Bell's palsy Inactivated influenza | expert causality review (IOM 2011) General | — | — | no increased risk detected | Institute of Medicine (Stratton K et al., eds.), 2011, Adverse Effects of Vaccines: Evidence and Causality, National Academies Press doi:10.17226/13164 |
Febrile seizures TIV 2010-11 + PCV13 same day | self-controlled risk interval (VSD) Children 6-59 mo, US (206,174) | IRR 5.9 (3.1–11.3) | 449 | increased risk | Tse A et al., 2012, Vaccine doi:10.1016/j.vaccine.2012.01.027; PMID 22361304 |
Febrile seizures TIV 2010-11 (adjusted for PCV13) | self-controlled risk interval (VSD) Children 6-59 mo, US | IRR 2.4 (1.2–4.7) | 125 | increased risk | Tse A et al., 2012, Vaccine doi:10.1016/j.vaccine.2012.01.027; PMID 22361304 |
Febrile seizures IIV3 + PCV (same day) | self-controlled risk interval (VSD) Children 6-23 mo, US 2006-2011 | IRR 3.5 (1.13–10.85) | — | increased risk | Duffy J et al., 2016, Pediatrics doi:10.1542/peds.2016-0320; PMID 27273711 |
Febrile seizures IIV3 + DTaP-containing vaccine (same day) | self-controlled risk interval (VSD) Children 6-23 mo, US | IRR 3.5 (1.52–8.07) | — | increased risk | Duffy J et al., 2016, Pediatrics doi:10.1542/peds.2016-0320; PMID 27273711 |
Febrile seizures IIV3 (alone, adjusted for concomitant vaccines) | self-controlled risk interval (VSD) Children 6-23 mo, US | IRR 0.46 (0.21–1.02) | — | no increased risk detected | Duffy J et al., 2016, Pediatrics doi:10.1542/peds.2016-0320; PMID 27273711 |
Fever days 1-2 (febrile seizure surrogate) IIV4 simultaneous vs 2 wk after DTaP+PCV13 | randomized controlled trial Children 12-16 mo, US (221) | RR 0.87 (0.36–2.1) | — | no increased risk detected | Walter EB et al., 2020, Pediatrics doi:10.1542/peds.2019-1909; PMID 32029684 |
Guillain-Barre syndrome 2009 H1N1 monovalent inactivated | self-controlled risk interval, meta-analysis of 6 US systems ~23 million vaccinated, US | IRR 2.35 (1.42–4.01) | 1.6 | increased risk | Salmon DA et al., 2013, Lancet doi:10.1016/S0140-6736(12)62189-8; PMID 23498095 |
Guillain-Barre syndrome 2009 H1N1 monovalent inactivated (MIV) | self-controlled risk interval (VSD) US, all ages (1.48 million MIV doses) | risk difference per million doses 5.0 (0.5–9.5) | 5 | increased risk | Greene SK et al., 2012, Am J Epidemiol doi:10.1093/aje/kws195; PMID 22582210 |
Guillain-Barre syndrome Seasonal TIV 2009-10 (without MIV) | self-controlled risk interval (VSD) US, all ages (1.72 million doses) | risk difference per million doses 1.1 (-3.1–5.4) | — | no increased risk detected | Greene SK et al., 2012, Am J Epidemiol doi:10.1093/aje/kws195; PMID 22582210 |
Guillain-Barre syndrome Seasonal influenza (1995-2006) | case-centered (KPNC) All ages, Kaiser Northern California (415 confirmed cases) | OR 1.1 (0.4–3.1) | — | no increased risk detected | Baxter R et al., 2013, Clin Infect Dis doi:10.1093/cid/cit222; PMID 23580737 |
Guillain-Barre syndrome 2009 H1N1 monovalent (Medicare) | self-controlled risk interval (FDA/CMS Medicare, chart confirmed) Medicare beneficiaries (mostly >=65 y), US 2009-2010 | IRR 2.41 (1.14–5.11) | 2.84 | increased risk | Polakowski LL et al., 2013, Am J Epidemiol doi:10.1093/aje/kwt051; PMID 23652165 |
Guillain-Barre syndrome 2009 H1N1 monovalent | active population-based surveillance (CDC Emerging Infections Program) 45 million persons, 10 US sites 2009-2010 | RR (adjusted) 1.57 (1.02–2.21) | 0.74 | increased risk | Wise ME et al., 2012, Am J Epidemiol doi:10.1093/aje/kws196; PMID 22582209 |
Narcolepsy Pandemrix (AS03 H1N1; Europe, not US-licensed) | retrospective cohort Children 4-19 y, Finland | RR 12.7 (6.1–30.8) | 62 | increased risk | Nohynek H et al., 2012, PLoS One doi:10.1371/journal.pone.0033536; PMID 22470453 |
Narcolepsy Pandemrix (AS03 H1N1; not US-licensed) | SCCS Children/young people 4-18 y, England | relative incidence 9.9 (2.1–47.9) | 18 | increased risk | Miller E et al., 2013, BMJ doi:10.1136/bmj.f794; PMID 23444425 |
Narcolepsy Pandemrix (AS03 H1N1; not US-licensed) | meta-analysis Children/adolescents and adults, multiple European countries | — | 54 | increased risk | Sarkanen TO et al., 2018, Sleep Med Rev doi:10.1016/j.smrv.2017.06.006; PMID 28847694 |
Narcolepsy US 2009 H1N1 and 2010-11 seasonal (non-adjuvanted; no Pandemrix) | cohort, observed vs expected (VSD) Persons <30 y, US (650,995 pandemic; 870,530 seasonal) | observed vs expected 0 | — | no increased risk detected | Duffy J et al., 2014, Neurology doi:10.1212/WNL.0000000000000987; PMID 25320099 |
Oculorespiratory syndrome Two particular trivalent inactivated vaccines (Canada, 3 seasons) | expert causality review (IOM 2011) Canada | — | — | increased risk | Institute of Medicine (Stratton K et al., eds.), 2011, Adverse Effects of Vaccines: Evidence and Causality, National Academies Press doi:10.17226/13164 |
Preterm birth (<37 wk) Trivalent inactivated influenza in pregnancy | matched cohort (VSD, 7 sites) Pregnant women, US 2004-2009 (57,554) | OR 0.97 (0.93–1.02) | — | no increased risk detected | Nordin JD et al., 2014, J Pediatr doi:10.1016/j.jpeds.2014.01.037; PMID 24582484 |
Spontaneous abortion Inactivated influenza in pregnancy (2012-15) | case-control (VSD) Pregnant women, US (1236 cases); previously vaccinated stratum 627 pairs | aOR 0.9 (0.6–1.5) | — | no increased risk detected | Donahue JG et al., 2019, Vaccine doi:10.1016/j.vaccine.2019.09.035; PMID 31540812 |
Spontaneous abortion Inactivated influenza containing H1N1pdm09 (2010-12) | case-control (VSD) Pregnant women, US (485 cases) | aOR 2.0 (1.1–3.6) | — | inconclusive | Donahue JG et al., 2017, Vaccine doi:10.1016/j.vaccine.2017.06.069; PMID 28917295 |
Mmr vaccines
| Outcome | Design & population | Estimate (95% CI) | Excess per million doses | Finding | Source |
|---|---|---|---|---|---|
ASD in children whose older siblings did not have ASD (2 doses vs none, age 5) MMR | cohort (commercial claims) US children with older siblings | RR 1.12 (0.78–1.59) | — | no increased risk detected | Jain A et al., 2015, JAMA doi:10.1001/jama.2015.3077; PMID 25898051 |
ASD in children with an older sibling with ASD (2 doses vs none, age 5) MMR | cohort (commercial claims) US children with older siblings (95,727) | RR 0.56 (0.31–1.01) | — | no increased risk detected | Jain A et al., 2015, JAMA doi:10.1001/jama.2015.3077; PMID 25898051 |
Autism MMR | cohort (national registry, Cox) Children born 1999-2010, Denmark (657,461) | HR 0.93 (0.85–1.02) | — | no increased risk detected | Hviid A et al., 2019, Ann Intern Med doi:10.7326/M18-2101; PMID 30831578 |
Autism MMR | expert causality review (IOM 2011) General | — | — | no increased risk detected | Institute of Medicine (Stratton K et al., eds.), 2011, Adverse Effects of Vaccines: Evidence and Causality, National Academies Press doi:10.17226/13164 |
Autism (cohort studies pooled) MMR | meta-analysis Children, multiple countries (5 cohort studies, 1,256,407 children) | OR 0.84 (0.7–1.01) | — | no increased risk detected | Taylor LE, Swerdfeger AL, Eslick GD, 2014, Vaccine doi:10.1016/j.vaccine.2014.04.085; PMID 24814559 |
Autism (strength-of-evidence rating) MMR | systematic review US-licensed vaccines, children | — | — | no increased risk detected | Maglione MA et al. (RAND/AHRQ), 2014, Pediatrics doi:10.1542/peds.2014-1079; PMID 25086160 |
Autism spectrum disorder Cumulative childhood schedule (antigen exposure) | case-control (3 MCOs) Children, US (256 ASD cases, 752 controls) | aOR per 25-unit antigen increase 0.999 (0.998–1.001) | — | no increased risk detected | DeStefano F et al., 2013, J Pediatr doi:10.1016/j.jpeds.2013.02.001; PMID 23545349 |
Autistic disorder MMR | cohort (national registry) Children born 1991-1998, Denmark (537,303) | RR 0.92 (0.68–1.24) | — | no increased risk detected | Madsen KM et al., 2002, N Engl J Med doi:10.1056/NEJMoa021134; PMID 12421889 |
Epilepsy after post-vaccination febrile seizure (vs febrile seizure while unvaccinated) MMR | cohort (national registry) Children with febrile seizures, Denmark | RR 0.7 (0.33–1.5) | — | no increased risk detected | Vestergaard M et al., 2004, JAMA doi:10.1001/jama.292.3.351; PMID 15265850 |
Febrile seizures MMRV (ProQuad) vs MMR+V same day | cohort (VSD, Poisson regression vs MMR+V) Children 12-23 mo, first dose, US (VSD 2000-2008) | RR 1.98 (1.43–2.73) | 430 | increased risk | Klein NP et al., 2010, Pediatrics doi:10.1542/peds.2010-0665; PMID 20587679 |
Febrile seizures MMRV or MMR+V, dose 2 | cohort (VSD) Children 4-6 y, US (VSD 2000-2008) | — | — | no increased risk detected | Klein NP et al., 2012, Pediatrics doi:10.1542/peds.2011-3198; PMID 22473362 |
Febrile seizures MMR | cohort (VSD, 4 HMOs, chart review) Children, US (679,942 children) | RR 2.83 (1.44–5.55) | — | increased risk | Barlow WE et al., 2001, N Engl J Med doi:10.1056/NEJMoa003077; PMID 11547719 |
Febrile seizures MMR | cohort (national registry) Children born 1991-1998, Denmark (537,171) | RR (incidence rate ratio) 2.75 (2.55–2.97) | — | increased risk | Vestergaard M et al., 2004, JAMA doi:10.1001/jama.292.3.351; PMID 15265850 |
Febrile seizures MMR | expert causality review (IOM 2011) General | — | — | increased risk | Institute of Medicine (Stratton K et al., eds.), 2011, Adverse Effects of Vaccines: Evidence and Causality, National Academies Press doi:10.17226/13164 |
ITP MMR (and other early-childhood vaccines) | cohort, risk vs control intervals (VSD) Children 6 wk-17 y, US (1.8 million) | — | — | increased risk | O'Leary ST et al., 2012, Pediatrics doi:10.1542/peds.2011-1111; PMID 22232308 |
Immune thrombocytopenic purpura (ITP) MMR | cohort, risk vs unexposed intervals (VSD) Children 12-15 mo, US (1,036,689 vaccinated children) | IRR 7.1 | 25 | increased risk | France EK et al., 2008, Pediatrics doi:10.1542/peds.2007-1578; PMID 18310189 |
Measles inclusion body encephalitis MMR (measles component) | expert causality review (IOM 2011) Individuals with demonstrated immunodeficiencies | — | — | increased risk | Institute of Medicine (Stratton K et al., eds.), 2011, Adverse Effects of Vaccines: Evidence and Causality, National Academies Press doi:10.17226/13164 |
Non-vaccine-targeted infections at 24-47 mo Cumulative childhood schedule (antigen count) | nested case-control (VSD) Children born 2003-2013, US (193 cases, 751 controls) | matched OR per 30-antigen increase 0.94 (0.84–1.07) | — | no increased risk detected | Glanz JM et al., 2018, JAMA doi:10.1001/jama.2018.0708; PMID 29509866 |
Other autism spectrum disorders MMR | cohort (national registry) Children born 1991-1998, Denmark | RR 0.83 (0.65–1.07) | — | no increased risk detected | Madsen KM et al., 2002, N Engl J Med doi:10.1056/NEJMoa021134; PMID 12421889 |
Transient arthralgia in women; transient arthralgia in children MMR (rubella component) | expert causality review (IOM 2011) Women; children | — | — | increased risk | Institute of Medicine (Stratton K et al., eds.), 2011, Adverse Effects of Vaccines: Evidence and Causality, National Academies Press doi:10.17226/13164 |
Type 1 diabetes MMR | case-control (VSD, 4 HMOs) Children born 1988-1997, US | OR 1.36 (0.7–2.63) | — | no increased risk detected | DeStefano F et al., 2001, Pediatrics doi:10.1542/peds.108.6.e112; PMID 11731639 |
Type 1 diabetes MMR | expert causality review (IOM 2011) General | — | — | no increased risk detected | Institute of Medicine (Stratton K et al., eds.), 2011, Adverse Effects of Vaccines: Evidence and Causality, National Academies Press doi:10.17226/13164 |
Covid-19 vaccines
| Outcome | Design & population | Estimate (95% CI) | Excess per million doses | Finding | Source |
|---|---|---|---|---|---|
23 serious outcomes incl. stroke, AMI, GBS, CVST, PE, Bell palsy (interim) BNT162b2 and mRNA-1273 | concurrent comparator risk interval (VSD) Ages >=12, US (11,845,128 doses) | — | — | no increased risk detected | Klein NP et al., 2021, JAMA doi:10.1001/jama.2021.15072; PMID 34477808 |
Anaphylaxis Pfizer-BioNTech BNT162b2 | cohort with chart confirmation (VSD) Ages >=12, US | incidence per million doses 4.8 (3.2–6.9) | — | increased risk | Klein NP et al., 2021, JAMA doi:10.1001/jama.2021.15072; PMID 34477808 |
Anaphylaxis Moderna mRNA-1273 | cohort with chart confirmation (VSD) Ages >=12, US | incidence per million doses 5.1 (3.3–7.6) | — | increased risk | Klein NP et al., 2021, JAMA doi:10.1001/jama.2021.15072; PMID 34477808 |
Guillain-Barre syndrome Janssen Ad26.COV2.S | cohort, risk vs comparison interval and vs mRNA (VSD) Ages >=12, US (483,053 Janssen doses) | RR (vs mRNA vaccines, head-to-head) 20.56 (6.94–64.66) | — | increased risk | Hanson KE et al., 2022, JAMA Netw Open doi:10.1001/jamanetworkopen.2022.8879; PMID 35471572 |
Guillain-Barre syndrome BNT162b2 and mRNA-1273 | cohort, risk vs comparison interval (VSD) Ages >=12, US (14.6 million mRNA doses) | RR (adjusted) 0.56 (0.21–1.48) | — | no increased risk detected | Hanson KE et al., 2022, JAMA Netw Open doi:10.1001/jamanetworkopen.2022.8879; PMID 35471572 |
Myocarditis SARS-CoV-2 infection (comparator, not a vaccine) | SCCS (England) Ages >=16, England (3,028,867 positive tests) | excess events per million infected 40 (38–41) | — | increased risk | Patone M et al., 2022, Nat Med doi:10.1038/s41591-021-01630-0; PMID 34907393 |
Myocarditis (any dose, all ages >=16) Pfizer-BioNTech BNT162b2 | cohort, Kaplan-Meier incidence (Clalit Health Services) Vaccinated members >=16 y, Israel (>2.5 million) | incidence per 100,000 vaccinated 2.13 (1.56–2.7) | — | increased risk | Witberg G et al., 2021, N Engl J Med doi:10.1056/NEJMoa2110737; PMID 34614329 |
Myocarditis (hospital admission or death) BNT162b2 dose 1 | SCCS (England) Ages >=16, England (16,993,389 vaccinated) | excess events per million vaccinated 1 (0–2) | 1 | increased risk | Patone M et al., 2022, Nat Med doi:10.1038/s41591-021-01630-0; PMID 34907393 |
Myocarditis (hospital admission or death) mRNA-1273 dose 2 | SCCS (England) Ages >=16, England (1,006,191 vaccinated) | excess events per million vaccinated 10 (7–11) | 10 | increased risk | Patone M et al., 2022, Nat Med doi:10.1038/s41591-021-01630-0; PMID 34907393 |
Myocarditis after dose 2 vs unvaccinated (all ages) Pfizer-BioNTech BNT162b2 | national active surveillance, rate ratio vs unvaccinated Israel, whole population (Dec 2020-May 2021) | rate ratio 2.35 (1.1–5.02) | — | increased risk | Mevorach D et al., 2021, N Engl J Med doi:10.1056/NEJMoa2109730; PMID 34614328 |
Myocarditis after dose 2, males 16-19 y Pfizer-BioNTech BNT162b2 | national active surveillance, rate ratio vs unvaccinated Males 16-19 y, Israel | rate ratio 8.96 (4.5–17.83) | 151 | increased risk | Mevorach D et al., 2021, N Engl J Med doi:10.1056/NEJMoa2109730; PMID 34614328 |
Myocarditis, all ages >=12 BNT162b2 dose 2 (homologous) | 4 cohort studies meta-analysed (Nordic registers) 23,122,522 residents, Denmark/Finland/Norway/Sweden | IRR (adjusted) 1.75 (1.43–2.14) | — | increased risk | Karlstad O et al., 2022, JAMA Cardiol doi:10.1001/jamacardio.2022.0583; PMID 35442390 |
Myocarditis, all ages >=12 mRNA-1273 dose 2 (homologous) | 4 cohort studies meta-analysed (Nordic registers) 23.1 million residents, Nordic countries | IRR (adjusted) 6.57 (4.64–9.28) | — | increased risk | Karlstad O et al., 2022, JAMA Cardiol doi:10.1001/jamacardio.2022.0583; PMID 35442390 |
Myocarditis, males 16-24 y BNT162b2 dose 2 | cohort (Nordic registers) Males 16-24 y, Nordic countries | IRR (adjusted) 5.31 (3.68–7.68) | — | increased risk | Karlstad O et al., 2022, JAMA Cardiol doi:10.1001/jamacardio.2022.0583; PMID 35442390 |
Myocarditis, males 16-24 y mRNA-1273 dose 2 | cohort (Nordic registers) Males 16-24 y, Nordic countries | IRR (adjusted) 13.83 (8.08–23.68) | — | increased risk | Karlstad O et al., 2022, JAMA Cardiol doi:10.1001/jamacardio.2022.0583; PMID 35442390 |
Myocarditis, males 16-29 y Pfizer-BioNTech BNT162b2 | cohort (Clalit Health Services) Males 16-29 y, Israel | incidence per 100,000 vaccinated 10.69 (6.93–14.46) | — | increased risk | Witberg G et al., 2021, N Engl J Med doi:10.1056/NEJMoa2110737; PMID 34614329 |
Myocarditis/myopericarditis (all ages >=12) Pfizer-BioNTech BNT162b2 | cohort (Danish registers, Cox) Ages >=12, Denmark (3,482,295 vaccinated) | HR (adjusted) 1.34 (0.9–2.0) | — | no increased risk detected | Husby A et al., 2021, BMJ doi:10.1136/bmj-2021-068665; PMID 34916207 |
Myocarditis/myopericarditis (all ages >=12) Moderna mRNA-1273 | cohort (Danish registers, Cox) Ages >=12, Denmark (498,814 vaccinated) | HR (adjusted) 3.92 (2.3–6.68) | — | increased risk | Husby A et al., 2021, BMJ doi:10.1136/bmj-2021-068665; PMID 34916207 |
Myocarditis/pericarditis, dose 2 Pfizer-BioNTech BNT162b2 | concurrent comparator risk interval (VSD) Adults 18-39 y, US (2,891,498 doses) | RR 14.3 (6.5–34.9) | 22.4 | increased risk | Goddard K et al., 2022, Vaccine doi:10.1016/j.vaccine.2022.07.007; PMID 35902278 |
Myocarditis/pericarditis, dose 2 Moderna mRNA-1273 | concurrent comparator risk interval (VSD) Adults 18-39 y, US (1,803,267 doses) | RR 18.8 (6.7–64.9) | 31.2 | increased risk | Goddard K et al., 2022, Vaccine doi:10.1016/j.vaccine.2022.07.007; PMID 35902278 |
Thrombosis with thrombocytopenia syndrome (TTS) Janssen Ad26.COV2.S | case series with reporting rate (VAERS-based, confirmed cases) - not a controlled study US, Dec 2020-Aug 2021 | reporting rate per million doses 3.83 | 3.83 | increased risk | See I et al., 2022, Ann Intern Med doi:10.7326/M21-4502; PMID 35038274 |
Hpv vaccines
| Outcome | Design & population | Estimate (95% CI) | Excess per million doses | Finding | Source |
|---|---|---|---|---|---|
13 other autoimmune diseases (composite) HPV vaccines (France) | cohort (national insurance databases) Girls 13-16 y, France | — | — | no increased risk detected | Miranda S et al., 2017, Vaccine doi:10.1016/j.vaccine.2017.06.030; PMID 28750853 |
Anaphylaxis HPV | expert causality review (IOM 2011) General | — | — | increased risk | Institute of Medicine (Stratton K et al., eds.), 2011, Adverse Effects of Vaccines: Evidence and Causality, National Academies Press doi:10.17226/13164 |
Autoimmune diseases (all combined) HPV vaccines | case-referent (PGRx, France 2008-2014) Females 11-25 y, France (478 cases, 1869 referents) | OR (adjusted) 0.58 (0.41–0.83) | — | no increased risk detected | Grimaldi-Bensouda L et al., 2017, J Autoimmun doi:10.1016/j.jaut.2017.01.005; PMID 28190705 |
Autoimmune disorders (any of 6 types) Gardasil (4vHPV) | case-control (PGRx, France) Females 14-26 y, France (211 cases, 875 controls) | OR (adjusted) 0.9 (0.5–1.5) | — | no increased risk detected | Grimaldi-Bensouda L et al., 2014, J Intern Med doi:10.1111/joim.12155; PMID 24206418 |
Autoimmune events (23 analysed) Gardasil (4vHPV) | register-based cohort Girls 10-17 y, Denmark and Sweden | — | — | no increased risk detected | Arnheim-Dahlstrom L et al., 2013, BMJ doi:10.1136/bmj.f5906; PMID 24108159 |
Celiac disease (only association remaining among 45 chronic diseases) Gardasil (4vHPV) | cohort + SCCS (national registers) Women 18-44 y, Denmark and Sweden (3,126,790) | RR 1.56 (1.29–1.89) | — | inconclusive | Hviid A et al., 2018, J Intern Med doi:10.1111/joim.12694; PMID 29044769 |
Guillain-Barre syndrome Gardasil (4vHPV) | cohort, incidence vs background (VSD) Ages 9-26 y, US 2006-2015 (2,773,185 doses) | incidence per million doses 0.36 | — | no increased risk detected | Gee J et al., 2017, Vaccine doi:10.1016/j.vaccine.2017.09.009; PMID 28935469 |
Guillain-Barre syndrome HPV vaccines (France) | cohort (national insurance databases) Girls 13-16 y, France 2008-2012 (2,252,716) | HR (adjusted) 3.78 (1.79–7.98) | — | increased risk | Miranda S et al., 2017, Vaccine doi:10.1016/j.vaccine.2017.06.030; PMID 28750853 |
MS / CNS acquired demyelinating syndromes HPV vaccine | nested case-control (Kaiser Southern California) Females 9-26 y (and all ages), US | OR 1.05 (0.62–1.78) | — | no increased risk detected | Langer-Gould A et al., 2014, JAMA Neurol doi:10.1001/jamaneurol.2014.2633; PMID 25329096 |
Multiple sclerosis Gardasil (4vHPV) | cohort (national registers) Females 10-44 y, Denmark and Sweden (3,983,824; 1.93 million doses) | IRR (adjusted) 0.9 (0.7–1.15) | — | no increased risk detected | Scheller NM et al., 2015, JAMA doi:10.1001/jama.2014.16946; PMID 25562266 |
Other CNS demyelinating diseases Gardasil (4vHPV) | cohort (national registers) Females 10-44 y, Denmark and Sweden | IRR (adjusted) 1.0 (0.8–1.26) | — | no increased risk detected | Scheller NM et al., 2015, JAMA doi:10.1001/jama.2014.16946; PMID 25562266 |
Pre-specified AEs (GBS, stroke, VTE, appendicitis, seizures, syncope, allergic reaction, anaphylaxis) Gardasil (4vHPV) | sequential surveillance vs historical/concurrent (VSD) Females 9-26 y, US (600,558 doses) | — | — | no increased risk detected | Gee J et al., 2011, Vaccine doi:10.1016/j.vaccine.2011.08.106; PMID 21907257 |
Pre-specified AEs (anaphylaxis, allergic reaction, appendicitis, GBS, CIDP, pancreatitis, seizure, stroke, syncope, VTE) Gardasil 9 (9vHPV) | near real-time sequential surveillance (VSD) Ages 9-26 y, US 2015-2017 (838,991 doses) | — | — | no increased risk detected | Donahue JG et al., 2019, Pediatrics doi:10.1542/peds.2019-1808; PMID 31740498 |
Skin infections Gardasil (4vHPV) | self-controlled risk interval (Kaiser California) Females 9-26 y, US | OR 1.8 (1.3–2.4) | — | increased risk | Klein NP et al., 2012, Arch Pediatr Adolesc Med doi:10.1001/archpediatrics.2012.1451; PMID 23027469 |
Syncope (day of vaccination) Gardasil (4vHPV) | self-controlled risk interval (Kaiser California) Females 9-26 y, US (189,629) | OR 6.0 (3.9–9.2) | — | increased risk | Klein NP et al., 2012, Arch Pediatr Adolesc Med doi:10.1001/archpediatrics.2012.1451; PMID 23027469 |
Syncope; deltoid bursitis Any injected vaccine (injection-related) | expert causality review (IOM 2011) General | — | — | increased risk | Institute of Medicine (Stratton K et al., eds.), 2011, Adverse Effects of Vaccines: Evidence and Causality, National Academies Press doi:10.17226/13164 |
Venous thromboembolism Gardasil (4vHPV) | SCCS (VSD) Ages 9-26 y, US 2008-2011 | IRR 0.92 (0.54–1.57) | — | no increased risk detected | Naleway AL et al., 2016, Vaccine doi:10.1016/j.vaccine.2015.10.006; PMID 26549361 |
Venous thromboembolism Gardasil (4vHPV) | register-based cohort Girls 10-17 y, Denmark and Sweden (997,585; 696,420 doses) | RR (adjusted) 0.86 (0.55–1.36) | — | no increased risk detected | Arnheim-Dahlstrom L et al., 2013, BMJ doi:10.1136/bmj.f5906; PMID 24108159 |
Dtap/tdap vaccines
| Outcome | Design & population | Estimate (95% CI) | Excess per million doses | Finding | Source |
|---|---|---|---|---|---|
Chorioamnionitis Tdap in pregnancy | retrospective cohort (VSD, 7 sites) Pregnancies, US 2010-2013 (197,564) | RR (adjusted rate ratio) 1.23 (1.17–1.28) | — | increased risk | DeSilva M et al., 2017, Vaccine doi:10.1016/j.vaccine.2017.05.041; PMID 28552511 |
Chorioamnionitis Tdap in pregnancy | retrospective cohort (VSD, 8 sites, IPW Cox) Pregnant people 15-49 y, US 2016-2018 (118,211) | HR (adjusted) 0.96 (0.9–1.03) | — | no increased risk detected | Greenberg V et al., 2023, Vaccine doi:10.1016/j.vaccine.2023.04.043; PMID 37117057 |
Chorioamnionitis (coded diagnosis) Tdap in pregnancy | retrospective cohort (VSD) Pregnant women, US 2010-2012 | RR (adjusted) 1.19 (1.13–1.26) | — | increased risk | Kharbanda EO et al., 2014, JAMA doi:10.1001/jama.2014.14825; PMID 25387187 |
Febrile seizures DTP (whole-cell; no longer used in US) | cohort (VSD) Children, US | RR 5.7 (1.98–16.42) | — | increased risk | Barlow WE et al., 2001, N Engl J Med doi:10.1056/NEJMoa003077; PMID 11547719 |
Febrile seizures Infant vaccine visits (median 4 vaccines incl. DTaP, PCV, Hib, IPV, HepB, RV) | self-controlled risk interval (VSD) Infants 1-5 mo, US 2006-2011 (585,342 vaccination visits) | IRR 23 (5.13–100.8) | — | increased risk | Duffy J et al., 2017, Pediatr Neurol doi:10.1016/j.pediatrneurol.2017.08.005; PMID 28958404 |
Guillain-Barre syndrome Td (tetanus-diphtheria) | case-centered (KPNC) Adolescents/adults, Kaiser Northern California | OR 1.4 (0.3–4.5) | — | no increased risk detected | Baxter R et al., 2013, Clin Infect Dis doi:10.1093/cid/cit222; PMID 23580737 |
Hypertensive disorders of pregnancy Tdap in pregnancy (before 20 wk) | retrospective cohort (VSD) Pregnant women, US 2010-2012 | RR (adjusted) 1.09 (0.99–1.2) | — | no increased risk detected | Kharbanda EO et al., 2014, JAMA doi:10.1001/jama.2014.14825; PMID 25387187 |
ITP Tdap | cohort, risk vs control intervals (VSD) Adolescents 11-17 y, US | — | — | inconclusive | O'Leary ST et al., 2012, Pediatrics doi:10.1542/peds.2011-1111; PMID 22232308 |
Neonatal sepsis Tdap in pregnancy | retrospective cohort (VSD) Infants of vaccinated vs unvaccinated mothers, US 2010-2013 | RR (adjusted rate ratio) 1.06 (0.91–1.23) | — | no increased risk detected | DeSilva M et al., 2017, Vaccine doi:10.1016/j.vaccine.2017.05.041; PMID 28552511 |
Preterm birth Tdap in pregnancy | retrospective cohort (VSD, 2 California sites) Pregnant women, singleton live births, US 2010-2012 (123,494) | RR (adjusted) 1.03 (0.97–1.09) | — | no increased risk detected | Kharbanda EO et al., 2014, JAMA doi:10.1001/jama.2014.14825; PMID 25387187 |
Seizures (febrile or afebrile) DTaP | risk-interval cohort + SCCS (VSD) Children 6 wk-23 mo, US (433,654) | IRR 0.91 | — | no increased risk detected | Huang WT et al., 2010, Pediatrics doi:10.1542/peds.2009-1496; PMID 20643726 |
Small for gestational age Tdap in pregnancy | retrospective cohort (VSD) Pregnant women, US 2010-2012 | RR (adjusted) 1.0 (0.96–1.06) | — | no increased risk detected | Kharbanda EO et al., 2014, JAMA doi:10.1001/jama.2014.14825; PMID 25387187 |
Type 1 diabetes Acellular pertussis-containing vaccines | case-control (VSD, 4 HMOs) Children born 1988-1997, US | OR 0.92 (0.53–1.57) | — | no increased risk detected | DeStefano F et al., 2001, Pediatrics doi:10.1542/peds.108.6.e112; PMID 11731639 |
Type 1 diabetes DT, TT or aP-containing vaccines | expert causality review (IOM 2011) General | — | — | no increased risk detected | Institute of Medicine (Stratton K et al., eds.), 2011, Adverse Effects of Vaccines: Evidence and Causality, National Academies Press doi:10.17226/13164 |
Rsv vaccines
| Outcome | Design & population | Estimate (95% CI) | Excess per million doses | Finding | Source |
|---|---|---|---|---|---|
11 prespecified outcomes (e.g., stroke, atrial fibrillation, anaphylaxis, encephalomyelitis; GBS reported separately) Arexvy (RSVPreF3+AS01) and Abrysvo (RSVPreF) | SCCS (FDA/CMS Medicare) Medicare beneficiaries >=65 y, US 2023-2024 (3.82 million vaccinated) | — | — | no increased risk detected | Lloyd PC et al., 2026, Vaccine doi:10.1016/j.vaccine.2026.128459; PMID 41833132 |
Guillain-Barre syndrome RSV disease (infection comparator, not a vaccine) | SCCS (Medicare claims 2011-2024) Adults >=65 y with medically attended RSV, US (452,471) | IRR (adjusted) 2.11 (1.01–4.37) | — | increased risk | Liang C et al., 2026, Clin Infect Dis doi:10.1093/cid/ciaf621; PMID 41234154 |
Guillain-Barre syndrome Abrysvo (RSVpreF, Pfizer) | SCCS (FDA/CMS Medicare claims, chart review when available) Medicare beneficiaries >=65 y, US May 2023-Jul 2024 | attributable risk per million doses 9 | 9 | increased risk | FDA Safety Communication, 'FDA Requires Guillain-Barre Syndrome (GBS) Warning in the Prescribing Information for RSV Vaccines Abrysvo and Arexvy', 2025-01-07 source |
Guillain-Barre syndrome Arexvy (RSVPreF3+AS01, GSK) | SCCS (FDA/CMS Medicare claims, chart review when available) Medicare beneficiaries >=65 y, US May 2023-Jul 2024 | attributable risk per million doses 7 | 7 | increased risk | FDA Safety Communication, 'FDA Requires Guillain-Barre Syndrome (GBS) Warning in the Prescribing Information for RSV Vaccines Abrysvo and Arexvy', 2025-01-07 source |
Guillain-Barre syndrome Abrysvo (RSVpreF) | SCCS (US EHR data platform, >270 million patients) US adults >=60 y (4,746,518 RSV vaccine recipients, both products) | excess cases per million doses 18.2 | 18.2 | increased risk | Fry SE et al., 2025, JAMA Netw Open doi:10.1001/jamanetworkopen.2025.8322; PMID 40343698 |
Guillain-Barre syndrome Arexvy (RSVPreF3+AS01) | SCCS (US EHR data platform) US adults >=60 y | excess cases per million doses 5.2 | 5.2 | inconclusive | Fry SE et al., 2025, JAMA Netw Open doi:10.1001/jamanetworkopen.2025.8322; PMID 40343698 |
Hypertensive disorders of pregnancy Abrysvo (RSVpreF) in pregnancy | retrospective cohort (2 NYC hospitals) Pregnant individuals, US 2023-2024 | HR (time-dependent) 1.43 (1.16–1.77) | — | inconclusive | Son M et al., 2024, JAMA Netw Open doi:10.1001/jamanetworkopen.2024.19268; PMID 38976271 |
Immune thrombocytopenic purpura Arexvy and Abrysvo | SCCS (US EHR data platform) US adults >=60 y (4,746,518 recipients) | — | — | no increased risk detected | Fry SE et al., 2025, JAMA Netw Open doi:10.1001/jamanetworkopen.2025.8322; PMID 40343698 |
Maternal and infant adverse events Abrysvo (RSVpreF) in pregnancy (MATISSE trial) | randomized controlled trial (phase 3) Pregnant women 24-36 wk, 18 countries (3682 vaccine, 3676 placebo) | — | — | no increased risk detected | Kampmann B et al., 2023, N Engl J Med doi:10.1056/NEJMoa2216480; PMID 37018474 |
Preterm birth Abrysvo (RSVpreF) in pregnancy | retrospective cohort (2 NYC hospitals) Pregnant individuals delivering >=32 wk, US 2023-2024 (2973) | HR (time-dependent) 0.93 (0.64–1.34) | — | no increased risk detected | Son M et al., 2024, JAMA Netw Open doi:10.1001/jamanetworkopen.2024.19268; PMID 38976271 |
Preterm birth GSK RSVPreF3-Mat (candidate maternal vaccine; never licensed) | randomized controlled trial (phase 3, stopped early) Pregnant women 18-49 y, 24-34 wk (5328) | RR 1.37 (1.08–1.74) | — | increased risk | Dieussaert I et al., 2024, N Engl J Med doi:10.1056/NEJMoa2305478; PMID 38477988 |
Preterm birth and other adverse pregnancy outcomes Maternal RSV vaccination (Abrysvo, 32-36 wk) | systematic review (RCTs + comparative observational studies) Pregnant individuals, US-licensed products | — | — | no increased risk detected | Senerth E et al., 2026, JAMA doi:10.1001/jama.2026.17871; PMID 42684247 |
Rotavirus vaccines
| Outcome | Design & population | Estimate (95% CI) | Excess per million doses | Finding | Source |
|---|---|---|---|---|---|
Intussusception Rotarix (RV1) | cohort, sequential vs historical and vs concurrent RV5 recipients (VSD) Infants 4-34 wk, US (207,955 RV1 doses) | RR (vs RV5) 9.4 (1.4–103.8) | — | increased risk | Weintraub ES et al., 2014, N Engl J Med doi:10.1056/NEJMoa1311738; PMID 24422678 |
Intussusception Rotarix (RV1) | self-controlled risk interval + cohort (FDA Mini-Sentinel) Infants, US (53,638 first doses) | — | — | inconclusive | Yih WK et al., 2014, N Engl J Med doi:10.1056/NEJMoa1303164; PMID 24422676 |
Intussusception RV1, RV5 and others (RCTs) | meta-analysis of RCTs Infants, 33 countries (25 trials, 200,594 participants) | RR 1.14 (0.49–2.64) | — | no increased risk detected | Lu HL et al., 2019, JAMA Netw Open doi:10.1001/jamanetworkopen.2019.12458; PMID 31584679 |
Intussusception (all doses) RotaTeq (RV5) | cohort vs historical background (VSD) Infants 4-34 wk, US (786,725 doses) | SIR 1.01 (0.62–1.54) | — | no increased risk detected | Shui IM et al., 2012, JAMA doi:10.1001/jama.2012.97; PMID 22318281 |
Intussusception (dose 1) RotaTeq (RV5) | self-controlled risk interval (FDA Mini-Sentinel) Infants 5-37 wk, US (507,874 first doses) | attributable risk per 100,000 first-dose recipients 1.5 (0.2–3.2) | — | increased risk | Yih WK et al., 2014, N Engl J Med doi:10.1056/NEJMoa1303164; PMID 24422676 |
Intussusception (dose 1) Rotarix (RV1) | SCCS (active hospital surveillance) Infants, Mexico | IRR (relative incidence) 5.3 (3.0–9.3) | — | increased risk | Patel MM et al., 2011, N Engl J Med doi:10.1056/NEJMoa1012952; PMID 21675888 |
Intussusception (dose 2) Rotarix (RV1) | SCCS + case-control (active hospital surveillance) Infants, Brazil | — | — | increased risk | Patel MM et al., 2011, N Engl J Med doi:10.1056/NEJMoa1012952; PMID 21675888 |
Kawasaki disease RotaTeq/Rotarix | self-controlled risk interval (VSD) Children <2 y, US, born 2006-2017 | RR (age-adjusted) 0.66 (0.4–1.09) | — | no increased risk detected | Kamidani S et al., 2022, Pediatrics doi:10.1542/peds.2022-058789; PMID 36349537 |
Hepatitis b vaccines
| Outcome | Design & population | Estimate (95% CI) | Excess per million doses | Finding | Source |
|---|---|---|---|---|---|
Anaphylaxis Childhood vaccines incl. hepatitis B, MMR, DTP/DT, Hib, OPV | cohort with chart review (VSD, 1991-1997) Children and adolescents, US (7,644,049 doses) | incidence per million doses 0.65 (0.21–1.53) | — | increased risk | Bohlke K et al., 2003, Pediatrics doi:10.1542/peds.112.4.815; PMID 14523172 |
Anaphylaxis All vaccines combined | cohort with chart review, Brighton definition (VSD, 2009-2011) Children and adults, US (25,173,965 doses) | incidence per million doses 1.31 (0.9–1.84) | — | increased risk | McNeil MM et al., 2016, J Allergy Clin Immunol doi:10.1016/j.jaci.2015.07.048; PMID 26452420 |
Anaphylaxis Hepatitis B (also MMR, varicella, influenza, meningococcal, tetanus toxoid) | expert causality review (IOM 2011) Hep B: yeast-sensitive individuals | — | — | increased risk | Institute of Medicine (Stratton K et al., eds.), 2011, Adverse Effects of Vaccines: Evidence and Causality, National Academies Press doi:10.17226/13164 |
MS / CNS acquired demyelinating syndromes Hepatitis B vaccine | nested case-control (Kaiser Southern California) All ages, US 2008-2011 (780 cases, 3885 controls) | OR 1.12 (0.72–1.73) | — | no increased risk detected | Langer-Gould A et al., 2014, JAMA Neurol doi:10.1001/jamaneurol.2014.2633; PMID 25329096 |
Multiple sclerosis Hepatitis B vaccine | nested case-control (Nurses' Health Study I and II) Women, US (192 MS cases, 645 controls) | RR (multivariate) 0.9 (0.5–1.6) | — | no increased risk detected | Ascherio A et al., 2001, N Engl J Med doi:10.1056/NEJM200102013440502; PMID 11172163 |
Relapse of multiple sclerosis Hepatitis B, tetanus, influenza vaccines | case-crossover MS patients, Europe (643 relapses) | RR (any vaccination) 0.71 (0.4–1.26) | — | no increased risk detected | Confavreux C et al., 2001, N Engl J Med doi:10.1056/NEJM200102013440501; PMID 11172162 |
Type 1 diabetes Hepatitis B vaccine | case-control (VSD, 4 HMOs) Children born 1988-1997, US | OR 0.81 (0.52–1.27) | — | no increased risk detected | DeStefano F et al., 2001, Pediatrics doi:10.1542/peds.108.6.e112; PMID 11731639 |
Varicella vaccines
| Outcome | Design & population | Estimate (95% CI) | Excess per million doses | Finding | Source |
|---|---|---|---|---|---|
Disseminated Oka VZV; vaccine-strain reactivation (incl. with meningitis/encephalitis) Varicella (Oka strain) | expert causality review (IOM 2011) General (mostly immunodeficient) | — | — | increased risk | Institute of Medicine (Stratton K et al., eds.), 2011, Adverse Effects of Vaccines: Evidence and Causality, National Academies Press doi:10.17226/13164 |
Herpes zoster in vaccinated cohort vs prevaccine-era unvaccinated children Varicella vaccine (Varivax) | prospective cohort (KPNC, 14 y) Children vaccinated in 2nd year of life 1995, US (7585) | RR 0.61 (0.43–0.89) | — | no increased risk detected | Baxter R et al., 2013, Pediatrics doi:10.1542/peds.2012-3303; PMID 23545380 |
Herpes zoster in vaccinated vs unvaccinated children Varicella vaccine (Varivax) | cohort (6 US integrated health care organizations) Children 0-17 y, US 2003-2014 (6,372,067) | incidence rate per 100,000 person-years 38 | — | no increased risk detected | Weinmann S et al., 2019, Pediatrics doi:10.1542/peds.2018-2917; PMID 31182552 |
Herpes zoster incidence, children <10 y Varicella vaccination program (population level) | population-based active surveillance (Antelope Valley, CA) Children <10 y, US 2000-2010 | incidence per 100,000 children 12.8 | — | no increased risk detected | Civen R et al., 2016, Pediatr Infect Dis J doi:10.1097/INF.0000000000001249; PMID 27622686 |
ITP Varicella vaccine | cohort, risk vs control intervals (VSD) Adolescents 11-17 y, US | — | — | inconclusive | O'Leary ST et al., 2012, Pediatrics doi:10.1542/peds.2011-1111; PMID 22232308 |
Type 1 diabetes Varicella vaccine | case-control (VSD, 4 HMOs) Children born 1988-1997, US | OR 1.16 (0.72–1.89) | — | no increased risk detected | DeStefano F et al., 2001, Pediatrics doi:10.1542/peds.108.6.e112; PMID 11731639 |
Pneumococcal vaccines
| Outcome | Design & population | Estimate (95% CI) | Excess per million doses | Finding | Source |
|---|---|---|---|---|---|
Febrile seizures PCV13 (adjusted for TIV) | self-controlled risk interval (VSD) Children 6-59 mo, US | IRR 2.5 (1.3–4.7) | 137 | increased risk | Tse A et al., 2012, Vaccine doi:10.1016/j.vaccine.2012.01.027; PMID 22361304 |
Febrile seizures (independent effect) PCV7 | self-controlled risk interval (VSD) Children 6-23 mo, US | IRR 1.98 (1.0–3.91) | — | increased risk | Duffy J et al., 2016, Pediatrics doi:10.1542/peds.2016-0320; PMID 27273711 |
Febrile seizures, urticaria/angioedema, asthma, thrombocytopenia, anaphylaxis Prevnar 13 (PCV13) vs PCV7 | cohort vs historical PCV7 (VSD) Children 1 mo-2 y, US 2010-2012 (599,229 doses) | — | — | no increased risk detected | Tseng HF et al., 2013, Vaccine doi:10.1016/j.vaccine.2013.03.040; PMID 23579258 |
Guillain-Barre syndrome PPSV23 (polysaccharide) | case-centered (KPNC) Adults, Kaiser Northern California | OR 0.7 (0.1–2.9) | — | no increased risk detected | Baxter R et al., 2013, Clin Infect Dis doi:10.1093/cid/cit222; PMID 23580737 |
Kawasaki disease Prevnar 13 (PCV13) | self-controlled risk interval (VSD) Children <2 y, US, born 2006-2017 | RR (age-adjusted) 0.75 (0.47–1.21) | — | no increased risk detected | Kamidani S et al., 2022, Pediatrics doi:10.1542/peds.2022-058789; PMID 36349537 |
Shingles vaccines
| Outcome | Design & population | Estimate (95% CI) | Excess per million doses | Finding | Source |
|---|---|---|---|---|---|
10 prespecified outcomes incl. stroke, anaphylaxis, GBS Shingrix (RZV) | sequential surveillance vs historical Zostavax and concurrent comparators (VSD) Adults >=50 y, US 2018-2019 (647,833 doses) | — | — | inconclusive | Nelson JC et al., 2023, Am J Epidemiol doi:10.1093/aje/kwac170; PMID 36193854 |
Any diagnosis (tree-temporal data mining) Shingrix (RZV) | self-controlled tree-temporal scan (MarketScan) Commercially insured adults >=50 y, US (1,014,329 doses) | — | — | no increased risk detected | Yih WK et al., 2022, Am J Epidemiol doi:10.1093/aje/kwac030; PMID 35152283 |
Guillain-Barre syndrome Shingrix (RZV) | SCCS, claims-based (FDA/CMS Medicare) Medicare beneficiaries >=65 y, US 2017-2020 | IRR 2.84 (1.53–5.27) | 3 | increased risk | Goud R et al., 2021, JAMA Intern Med doi:10.1001/jamainternmed.2021.6227; PMID 34724025 |
Guillain-Barre syndrome Shingrix (RZV) vs Zostavax (ZVL) | cohort (Medicare) Medicare beneficiaries >=65 y, US (849,397 RZV; 1,817,099 ZVL) | RR 2.34 (1.01–5.41) | — | increased risk | Goud R et al., 2021, JAMA Intern Med doi:10.1001/jamainternmed.2021.6227; PMID 34724025 |
Meningococcal vaccines
| Outcome | Design & population | Estimate (95% CI) | Excess per million doses | Finding | Source |
|---|---|---|---|---|---|
26 prespecified events of interest (other than Bell's palsy) Menveo (MenACWY-CRM) | cohort with SCCS (Kaiser Southern California) Ages 11-21 y, US | — | — | no increased risk detected | Tseng HF et al., 2017, Pediatrics doi:10.1542/peds.2016-2084; PMID 28025240 |
Anaphylaxis Meningococcal | expert causality review (IOM 2011) General | — | — | increased risk | Institute of Medicine (Stratton K et al., eds.), 2011, Adverse Effects of Vaccines: Evidence and Causality, National Academies Press doi:10.17226/13164 |
Bell's palsy Menveo (MenACWY-CRM) | cohort with SCCS (Kaiser Southern California) Ages 11-21 y, US 2011-2013 (48,899) | relative incidence (adjusted) 2.9 (1.1–7.5) | — | inconclusive | Tseng HF et al., 2017, Pediatrics doi:10.1542/peds.2016-2084; PMID 28025240 |
Guillain-Barre syndrome Menactra (MCV4, MenACWY-D) | retrospective cohort (5 US health plans) Ages 11-21 y, US 2005-2008 (>1.4 million vaccinations) | attributable risk (upper 95% bound) 0 | — | no increased risk detected | Velentgas P et al., 2012, Pharmacoepidemiol Drug Saf doi:10.1002/pds.3321; PMID 22807266 |
Yellow fever vaccines
| Outcome | Design & population | Estimate (95% CI) | Excess per million doses | Finding | Source |
|---|---|---|---|---|---|
Hospitalization for virologically confirmed dengue in seronegative recipients Dengvaxia (CYD-TDV; dengue, not yellow fever) | case-cohort reanalysis of 3 RCTs Dengue-seronegative participants 2-16 y, Asia/Latin America | HR 1.75 (1.14–2.7) | — | increased risk | Sridhar S et al., 2018, N Engl J Med doi:10.1056/NEJMoa1800820; PMID 29897841 |
YEL-AND (neurologic disease) Yellow fever vaccine (17D) | PASSIVE reporting rate (VAERS) per doses distributed - not a controlled study US travelers 2007-2013 | reporting rate per 100,000 doses distributed 0.8 | 8 | increased risk | Lindsey NP et al., 2016, J Travel Med doi:10.1093/jtm/taw045; PMID 27378369 |
YEL-AVD (viscerotropic disease) Yellow fever vaccine (17D) | PASSIVE reporting rate (VAERS) per doses distributed - not a controlled study US travelers 2007-2013 | reporting rate per 100,000 doses distributed 0.3 | 3 | increased risk | Lindsey NP et al., 2016, J Travel Med doi:10.1093/jtm/taw045; PMID 27378369 |
Hib vaccines
| Outcome | Design & population | Estimate (95% CI) | Excess per million doses | Finding | Source |
|---|---|---|---|---|---|
Medically attended fever, 1-2 year olds Pentacel (DTaP-IPV-Hib) | group sequential cohort vs historical DTaP recipients (VSD) Children 1-2 y, US | RR 1.83 (1.34–2.5) | — | increased risk | Nelson JC et al., 2013, Am J Epidemiol doi:10.1093/aje/kws317; PMID 23292957 |
Type 1 diabetes Hib conjugate | birth-cohort comparison (trial cohorts) Children, Finland (128,936 + 116,352) | RR 1.01 | — | no increased risk detected | Karvonen M et al., 1999, BMJ doi:10.1136/bmj.318.7192.1169; PMID 10221937 |
Type 1 diabetes Hib | case-control (VSD, 4 HMOs) Children born 1988-1997, US (252 cases, 768 controls) | OR 1.14 (0.51–2.57) | — | no increased risk detected | DeStefano F et al., 2001, Pediatrics doi:10.1542/peds.108.6.e112; PMID 11731639 |
Polio vaccines
| Outcome | Design & population | Estimate (95% CI) | Excess per million doses | Finding | Source |
|---|---|---|---|---|---|
8 prespecified AEs (meningitis/encephalitis, seizures, stroke, GBS, SJS, anaphylaxis, serious allergic, serious local reactions) Kinrix (DTaP-IPV) | sequential surveillance vs historical rates (VSD) Children 4-6 y, US 2009-2012 (201,116) | — | — | no increased risk detected | Daley MF et al., 2014, Vaccine doi:10.1016/j.vaccine.2014.03.063; PMID 24699471 |
Fever, seizure, meningitis/encephalitis/myelitis, allergic reactions, anaphylaxis, GBS, invasive Hib Pentacel (DTaP-IPV-Hib) | group sequential cohort vs historical DTaP recipients (VSD) Children, US 2008-2011 (149,337) | — | — | no increased risk detected | Nelson JC et al., 2013, Am J Epidemiol doi:10.1093/aje/kws317; PMID 23292957 |
Hepatitis a vaccines
| Outcome | Design & population | Estimate (95% CI) | Excess per million doses | Finding | Source |
|---|---|---|---|---|---|
ITP Hepatitis A vaccine | cohort, risk vs control intervals (VSD) Children 7-17 y, US | — | — | inconclusive | O'Leary ST et al., 2012, Pediatrics doi:10.1542/peds.2011-1111; PMID 22232308 |
Common questions
What is the difference between VAERS and a vaccine safety study?
VAERS collects reports from anyone and has no comparison group, so it cannot show whether an event is more common after vaccination. Controlled studies such as the Vaccine Safety Datalink compare vaccinated people with an unvaccinated group or with the same people in a control time window, which lets them estimate whether a risk is raised and how many extra cases occur per million doses.
Which vaccine risks have controlled studies confirmed?
Examples in this table include febrile seizures after MMRV (compared with separate MMR and varicella), intussusception after rotavirus vaccines, Guillain-Barré syndrome after some influenza, Shingrix and RSV vaccines, and myocarditis after mRNA COVID-19 vaccines in young males — each with an estimate of excess cases per million doses.
Have studies found that vaccines cause autism?
The large cohort and case-control studies in this table, including nationwide Danish cohorts of more than 650,000 children, found no increased risk of autism after MMR vaccination.
Compiled 2026-10-09. See also observed vs expected and how a signal becomes a finding. Not medical advice.