Hepatitis A vaccine !
Inactivated whole hepatitis A virus with aluminium adjuvant. It prevents hepatitis A and can be used soon after exposure.
Updated 2026-11-01
Also called: HepA vaccine, Hepatitis A and B (combination)
The figure shows the hepatitis A virus capsid; the vaccine contains the whole virus inactivated with formalin.
Mechanism of action
Formalin-inactivated virus adsorbed to aluminium induces neutralising antibodies against the capsid. Hepatitis A spreads by the faecal-oral route, is often silent in young children and more often causes jaundice in adults; it does not become chronic. The vaccine can also be given after exposure, as the incubation period leaves time for antibodies to form.
- Inactivated whole virus is injected with aluminium adjuvant
- Neutralising antibodies form against the capsid
- Antibodies stop virus from the gut reaching the liver
- Given within two weeks of exposure, it can still prevent disease
Pharmacokinetics
- Onset and duration
- Used for post-exposure prophylaxis within two weeks of exposure
Indications
- Prevention of hepatitis A Viral hepatitis →
- Post-exposure prophylaxis in unvaccinated people aged 12 months or older
Adverse effects
Common
- Pain, redness and swelling at the injection site
- Fever, headache
Contraindications
- Severe allergic reaction to a previous dose or a component
- Combined hepatitis A and B vaccine: also the hepatitis B vaccine contraindications (yeast)
Key interactions
- Normal immunoglobulin
- Alternative or complement after exposure: for infants too young to vaccinate or when the vaccine is contraindicated; immunocompromised contacts receive both
What is monitored
- Series complete
- Contacts of a case identified for post-exposure prophylaxis
Administration and safety
- Intramuscular route
- Check whether it is a paediatric or adult formulation, or the combined A + B product
- Record the batch and product
Nursing care
- Ask about reactions to previous doses
- Identify exposed contacts for prompt prophylaxis
- Teach hand hygiene and safe water and food
Pregnancy and breastfeeding
Safety data from vaccination in pregnancy have shown no increased risk for most adverse outcomes.
Test yourself
Think of the answer, then tap the question to see it.
Does hepatitis A become chronic?
No: a chronic carrier state has not been described, although relapsing or prolonged illness can occur.
Why are many young children with hepatitis A not diagnosed?
Most infections in young children are asymptomatic; jaundice is more frequent in older children and adults.
What can be given after exposure to an unvaccinated person aged 12 months or older?
Hepatitis A vaccine within two weeks of exposure; immunoglobulin is added or used in certain groups.
Related drugs
Related conditions
← Back to the class: Viral vaccines
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Chapter 9: Hepatitis A | Pink Book | CDC (Centers for Disease Control and Prevention, 2021); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake
Representative model, for educational purposes only.