Havrix

Havrix is an injectable solution vaccine containing inactivated hepatitis A virus adsorbed on aluminium hydroxide, supplied in a standard dose for intramuscular administration. The product is a prescription‑only vaccine approved in the European Union for the prevention of hepatitis A infection. It presents the viral antigen to the immune system to stimulate protective antibodies. It is administered as a single dose or as part of a two‑dose series.

Havrix is indicated for the active immunisation against hepatitis A virus infection.

- Provides primary prevention for travelers to endemic regions and individuals with occupational exposure. - Included in routine childhood vaccination schedules for children aged one year and older. - Can be used in outbreak control to quickly immunise at‑risk populations. - Recommended for persons with chronic liver disease to reduce severe hepatitis A outcomes. - May be administered to individuals with clotting factor disorders when intramuscular injection is appropriate. - Used as part of pre‑exposure prophylaxis for people living in areas with high hepatitis A incidence.

Common and serious adverse reactions have been reported following Havrix administration, most of which are mild and self‑limiting.

Common: - Pain, redness, or swelling at the injection site lasting 1–3 days. - Mild fever or chills occurring within 24 hours after vaccination. - Headache, fatigue, or muscle aches that resolve spontaneously. - Nausea or loss of appetite for a short duration. - Transient joint pain or arthralgia reported in a small number of recipients.

Serious: - Severe allergic reaction (anaphylaxis) with difficulty breathing, hives, or swelling of the face. - High fever (>39°C) persisting beyond 48 hours. - Neurological events such as Guillain‑Barré syndrome, though extremely rare. - Severe rash or urticaria requiring medical attention. - Persistent vomiting or diarrhea lasting more than 48 hours.

Before administering Havrix, healthcare providers should evaluate patient history and consider specific safety precautions.

- Do not vaccinate individuals with a known severe allergy to any vaccine component, including aluminium hydroxide. - Postpone vaccination in persons experiencing an acute febrile illness until recovery. - Use with caution in immunocompromised patients, as response may be reduced. - Pregnancy and lactation status should be assessed; benefits must outweigh potential risks. - Children under one year of age are not eligible for this vaccine. - Patients with clotting disorders should receive the injection using a subcutaneous route if intramuscular is contraindicated.

Havrix may interact with other vaccines or biologic products; certain combinations should be avoided or used with caution.

Avoid: - Live attenuated vaccines administered within 4 weeks before or after Havrix. - Immunoglobulin or blood products given within 2 weeks of vaccination. - Concurrent administration of other inactivated vaccines without proper spacing. - Administration of other hepatitis vaccines (e.g., hepatitis B) on the same day is not recommended.

Use with caution: - Immunosuppressive therapy, including corticosteroids, may diminish vaccine efficacy. - Pregnancy, as safety data are limited; risk‑benefit assessment required. - Chronic liver disease patients may need closer monitoring after vaccination. - Individuals with autoimmune disorders should be evaluated before immunisation.