Epidemiology And Rationale
- Hepatitis A virus causes benign, asymptomatic infection in young children.
- Disease severity and mortality increase significantly in adolescents and adults.
- Shifting endemicity in India leaves older populations susceptible, contributing to recurring outbreaks and fulminant hepatic failure.
Types Of Vaccines
| Feature | Inactivated Vaccine | Live Attenuated Vaccine |
|---|
| Viral strain | HM 175 or GBM strain | H2 or LA-1 strain |
| Adjuvant | Aluminum hydroxide or virosome | None |
| Route | Intramuscular | Subcutaneous |
| Schedule | Two doses | Single dose |
| Immunocompromised | Safe for use | Contraindicated |
| Available brands | Havrix, Avaxim, Hapibev, Havisure, Havpur | Biovac A |
Vaccination Schedule And Administration
- Minimum age for vaccination initiation remains 12 months.
- Inactivated schedule entails two intramuscular doses administered 6 to 18 months apart.
- Live attenuated schedule requires a single subcutaneous dose.
- Catch-up vaccination requires pre-vaccination antibody screening for children older than 10 years due to high baseline seropositivity.
- Protective threshold defined as antibody levels between 10 and 33 mIU/ml.
- Both vaccine types generate long-lasting, possibly life-long protection without requiring routine boosters in immunocompetent individuals.
High-Risk Indications
- Chronic liver disease patients.
- Carriers of hepatitis b and c viruses.
- Congenital or acquired immunodeficiency.
- Organ transplant recipients.
- Travelers visiting highly endemic areas.
- Seronegative adolescents leaving for residential schools.
Post-Exposure Prophylaxis
- Vaccine administration preferred over immunoglobulin due to active immunity induction and longer protection.
- Administer single vaccine dose within two weeks of exposure for contacts aged 1 to 40 years.
- Administer intramuscular immunoglobulin for infants under 1 year and adults over 40 years.
- Immunocompromised contacts require both vaccine and specific immunoglobulin.
Storage Guidelines
- Maintain continuous cold chain between 2 and 8 degrees celsius.
- Do not freeze.
- Protect live vaccines from light.
