Havrix

Havrix is an injectable vaccine containing inactivated hepatitis A virus and the adjuvant algeldrate, supplied as a lyophilized powder for reconstitution. It is marketed in the European Union and is classified as a hepatitis A prophylaxis vaccine. The product is administered intramuscularly to stimulate active immunity against hepatitis A infection. Formulation is designed for use in adults as part of immunization schedules, and it does not contain live virus.

Havrix is indicated for the prevention of hepatitis A infection in individuals who have not been previously immunized.

- Primary prophylaxis for travelers to endemic areas. - Routine immunization of children according to national schedules. - Post‑exposure prophylaxis for close contacts of confirmed cases. - Immunization of individuals with chronic liver disease. - Use in outbreak control settings as recommended by public health authorities. - Administration to persons with occupational risk (e.g., laboratory workers handling hepatitis A virus).

Following intramuscular injection, Havrix may be associated with transient local and systemic reactions.

Common: - Pain, redness, or swelling at the injection site. - Low‑grade fever. - Headache. - Fatigue or mild malaise. - Nausea. - Muscle aches. - Local itching.

Serious: - Severe allergic reaction (anaphylaxis). - Guillain‑Barré syndrome (rare). - High fever with chills. - Persistent joint pain. - Neurological symptoms such as weakness. - Severe rash.

Healthcare providers should assess individual risk factors and medical history before administering Havrix.

- Defer vaccination in persons with known severe allergy to any vaccine component. - Evaluate immunocompromised patients, as response may be reduced. - Consider timing of other vaccines; separate administration by at least 4 weeks when possible. - Counsel pregnant or breastfeeding women; data are limited, so use only if benefits outweigh risks. - Monitor for immediate hypersensitivity reactions for at least 15 minutes after injection. - Document prior hepatitis A vaccination to avoid unnecessary repeat dosing.

Havrix generally has a low potential for drug interactions, but certain circumstances warrant caution.

Avoid: - Concomitant administration of other injectable vaccines containing live attenuated viruses (e.g., measles, mumps, rubella) in the same syringe.

Use with caution: - Simultaneous receipt of other inactivated vaccines (e.g., influenza) may increase local reactogenicity. - Immunoglobulin or blood products given within 2 weeks before or after vaccination may diminish immune response. - Antihistamines may mask early signs of an allergic reaction. - Corticosteroid therapy may reduce vaccine efficacy.