Havrix Adults (Hepatitis A Virus (Inactivated), Algeldrate)

Havrix Adults is indicated for the prevention of hepatitis A infection in adults who have not been previously immunized or who require booster protection.

• Primary prophylaxis for hepatitis A in healthy adults.
• Protection for travelers to regions with intermediate or high hepatitis A endemicity.
• Immunization of individuals with occupational exposure to hepatitis A (e.g., laboratory personnel).
• Use in outbreak settings to quickly establish herd immunity.
• Booster dose for adults previously vaccinated when antibody levels decline (as determined by serology).
• Vaccination of individuals with chronic liver disease to reduce risk of severe hepatitis A outcomes.

The safety profile of Havrix Adults reflects typical vaccine reactions, most of which are mild, self‑limiting, and resolve without medical intervention. These reactions are consistent with the body's immune response to the inactivated virus and adjuvant.

Common

• Pain, redness, or swelling at the injection site, typically lasting 1–3 days.
• Low‑grade fever within 24–48 hours, often accompanied by mild chills.
• Headache or mild fatigue that resolves spontaneously.
• Transient muscle aches or joint discomfort lasting a few days.

Serious

• Severe allergic reaction (anaphylaxis), characterized by difficulty breathing, hives, or swelling of the face and throat.
• Rare neurologic events such as Guillain‑Barré syndrome, presenting with muscle weakness and tingling sensations.

Before administering Havrix Adults, healthcare providers should assess individual risk factors and follow recommended safety guidelines.

• Verify no severe allergic reaction to any vaccine component, especially algeldrate.
• Defer vaccination in persons with acute moderate or severe illness until recovery.
• Use caution in individuals with weakened immune systems; vaccine may be less effective.
• Consider postponement during pregnancy; data are limited, and risk‑benefit assessment is required.
• Avoid administration to persons with known thrombocytopenia or bleeding disorders without appropriate precautions.
• Observe the patient for at least 15 minutes after injection for immediate hypersensitivity.
• Do not administer intravascularly; ensure proper intramuscular technique.

Havrix Adults may interact with other agents that affect immune response or increase the risk of hypersensitivity.

Avoid

• Concurrent administration with other injectable vaccines containing live attenuated viruses without appropriate spacing.
• Use of immunosuppressive therapy that markedly reduces vaccine efficacy.

Use with caution

• Antipyretics (e.g., acetaminophen, ibuprofen) may mask fever after vaccination, potentially delaying detection of adverse events.
• Blood products or immunoglobulins administered within three months can interfere with the development of protective antibodies.
• Chronic corticosteroid use may diminish immune response; serologic testing can assess adequacy of protection.
• Allergy medications may conceal early signs of an allergic reaction, so observation after injection remains important.