Havrix (Hepatitis A Virus (Inactivated), Algeldrate)

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

• Active immunization of adults and children aged 12 months and older.
• Pre‑travel prophylaxis for persons traveling to regions with intermediate or high hepatitis A endemicity.
• Post‑exposure prophylaxis when administered within two weeks of exposure.
• Use in outbreak settings to quickly establish herd immunity.
• Immunization of individuals with chronic liver disease to reduce risk of severe hepatitis A.

The safety profile of Havrix reflects the typical reactions observed with inactivated viral vaccines.

Common

• Mild pain, redness, or swelling at the injection site, usually resolving within a few days.
• Low‑grade fever lasting 24–48 hours, sometimes accompanied by chills.
• Headache or fatigue that is transient and does not interfere with daily activities.
• Muscle aches or joint discomfort that are mild and short‑lived.

Serious

• Severe allergic reaction (anaphylaxis) with symptoms such as difficulty breathing, hives, swelling of the face, throat, or tongue, and a rapid drop in blood pressure, requiring immediate medical attention.
• Guillain‑Barré syndrome, a rare immune‑mediated neurological disorder that may cause muscle weakness and paralysis, reported in a very small number of vaccine recipients.

Precautions for Havrix focus on patient history, immune status, and appropriate timing of vaccination.

• Defer vaccination in individuals with known severe allergy to any vaccine component, including algeldrate.
• Postpone administration during acute moderate or severe illness until recovery.
• Assess immune competence; immunocompromised patients may have reduced antibody response.
• Consider age-specific dosing; children under 12 months are not recommended for this vaccine.
• Evaluate pregnancy status; vaccine is generally avoided unless benefits outweigh risks.
• Review history of Guillain‑Barré syndrome; discuss potential risks with healthcare provider.

Because Havrix is an inactivated vaccine, drug interactions are limited, but certain medications and conditions may affect its efficacy or safety.

Avoid

• Concurrent administration of immunosuppressive agents (e.g., high‑dose corticosteroids) that may blunt the immune response.
• Live‑virus vaccines given within four weeks before or after Havrix, as they may interfere with immune priming.

Use with caution

• Antipyretics such as acetaminophen or ibuprofen taken prophylactically, which might reduce antibody titers.
• Blood products or immunoglobulins administered within three months, potentially affecting vaccine‑induced immunity.
• Chronic liver disease patients; monitor response and consider additional dosing.
• Patients receiving chemotherapy should be evaluated for adequate serologic response.