Question explored with the scientific record
What are the complications with hepatitis A vaccine?
The short version: the evidence for hepatitis A vaccine complications is thin, short-term, and mostly from studies that did not compare vaccinated to unvaccinated people.
The one study that directly looked at hepatitis A vaccine in children was a 2016 Australian observational study of a combined hepatitis A and typhoid shot [7]. It followed 425 children for only three days after vaccination. No serious adverse events were reported, but 70.5% had a sore arm, 16% had redness, and 11% had swelling at the injection site. Systemic reactions like tiredness (5.9%), headache (4.2%), and fever (3.4%) were less common. The study had no control group, relied on parent reports, and the follow-up was too short to catch delayed reactions. This is the best published data we have for hepatitis A vaccine in children, and it is weak.
The rest of the retrieved evidence is about different vaccines entirely: hepatitis B, COVID-19, Tdap, polio, and others [1, 2, 3, 4, 5, 6, 8, 9, 10, 11, 12]. None of it answers the question about hepatitis A vaccine complications. A 1999 neurology review [1] covers neurologic risks of many vaccines but does not mention hepatitis A. A 2022 Chinese study [2] is about hepatitis B vaccine reporting, not hepatitis A.
What the evidence does not cover matters more than what it does. No long-term safety studies exist in this retrieval. No studies comparing vaccinated to unvaccinated people over years. No data on autoimmune conditions, neurologic disorders, or chronic immune dysfunction after hepatitis A vaccination. The mechanism of harm from injected aluminum adjuvants and immune imprinting applies here as it does to other vaccines, but no study in this set tested it for hepatitis A specifically.
My call: the short-term local reactions are documented and common, but the evidence base is too thin to assess serious or long-term complications. Confidence: low.
Sources used 12
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Assessment: Neurologic risk of immunization [RETIRED]
A comprehensive American Academy of Neurology Therapeutics and Technology Assessment Subcommittee assessment reviewing neurologic adverse events after immunization, concluding vaccines have an excellent safety profile with rare neurologic events, outlining how causality is judge…
DOI: 10.1212/WNL.52.8.1546 - Change in adverse event reporting following immunization of hepatitis B vaccine among infants between 2013 to 2020 before and after the vaccine administration law in China DOI: 10.3389/fimmu.2022.956473
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Safety and Tolerability of SARS-CoV2 Emergency-Use Authorized Vaccines for Allogeneic Hematopoietic Stem Cell Transplant Recipients
Retrospective study evaluating safety, tolerability, GVHD impact, and SARS-CoV-2 infection after SARS-CoV2 Emergency-Use Authorized vaccines in allogeneic hematopoietic stem cell transplant recipients, finding vaccines were well tolerated with some GVHD activity and few adverse …
DOI: 10.1016/j.jtct.2021.07.008 -
Immune-related adverse events of COVID-19 vaccination in skin cancer patients receiving immune-checkpoint inhibitor treatment
COVID-19 vaccination in skin cancer patients receiving immune-checkpoint inhibitors appears generally safe with no clear increase in immune-related adverse events, though vaccination timing around ICI cycles may influence irAE onset.
DOI: 10.1007/s00262-021-03133-w -
Adjuvanted recombinant HBV vaccine (HBV-AS04) is effective over extended follow-up in dialysis population. An open-label non randomized trial
HBV-AS04 vaccine achieves 81.5% seroprotection in dialysis patients, with 77% persistence at 72 months, and age is an independent predictor; no serious adverse events occurred.
DOI: 10.1016/j.clinre.2020.01.010 -
Immune Response to Hepatitis B Vaccine in Hemodialysis Patients
In an open-label study, hemodialysis patients given a 4-dose schedule of 40 µg MSD hepatitis B vaccine at months 0, 1, 5, and 6 developed protective anti-HBs titers in 92% (19/22) of patients, with geometric mean titers that were satisfactory but lower than in healthy controls, …
DOI: 10.1159/000184120 -
The tolerability of a combined hepatitis A and typhoid vaccine in children aged 2–16 years: an observational study
This prospective observational study in Australian travel clinics assessed the tolerability of the combined hepatitis A and typhoid vaccine (Vivaxim) in children aged 2–16 years, finding no serious adverse events, higher local reactogenicity than monovalent vaccines, and general…
DOI: 10.1093/jtm/tav023 -
Delivery of immunoreactive antigen using a controllable needle-free jet injector
Controllable needle-free jet injection can intradermally deliver Hepatitis B surface antigen in mice with immune responses that are non-inferior to conventional needle-based delivery, though titers reflect differences in delivered antigen volume and injection parameters.
DOI: 10.1016/j.jconrel.2017.05.003 -
Complex Regional Pain Syndrome in a Young Boy After Receiving a Diphtheria, Tetanus, and Acellular Pertussis Vaccine
A case report describes a young boy who developed complex regional pain syndrome after a Tdap vaccination, with complete resolution after aggressive physical therapy.
DOI: 10.36076/pmcr.2020/4/203 -
The Allocation and Rationing of High-Cost Services-Reply
The letter argues that low-dose intradermal hepatitis B vaccine is less immunogenic and less safe than the standard intramuscular dose, based on comparisons of antibody levels and adverse reactions.
DOI: 10.1001/jama.1986.03380030052024 -
Granulocyte–macrophage colony‐stimulating factor enhances the efficacy of hepatitis B virus vaccine in previously unvaccinated haemodialysis patients
GM-CSF as an adjuvant significantly increased HBV vaccine seroprotection rates in haemodialysis patients (100% vs 44%) with earlier protective antibody responses and acceptable safety.
DOI: 10.1046/j.1365-2893.1999.00180.x -
Risk of Invasive Haemophilus influenzae Infection During Pregnancy and Association With Adverse Fetal Outcomes
This national surveillance study investigates the risk of invasive Haemophilus influenzae infection during pregnancy and its association with adverse fetal outcomes, revealing a significantly higher incidence in parturients and poor pregnancy outcomes linked to unencapsulated st…
DOI: 10.1097/01.sa.0000460949.33944.a6