Influvac Tetra (B/Phuket/3073/2013-Like Virus (B/Phuket/3073/2013, Wild Type), Influenza Virus B/Austria/1359417/202)

Influvac Tetra is indicated for immunization against influenza viruses within the seasonal flu disease family.

• Seasonal influenza: provides protection against the four influenza virus strains included in the vaccine, reducing the risk of infection.
• High‑risk populations: helps lower the incidence of flu‑related complications in elderly, pregnant persons, and individuals with chronic medical conditions.
• Outbreak control: contributes to community immunity during influenza epidemics, supporting public health vaccination programs.

• Influvac Tetra contains inactivated, split virion antigens from two influenza A subtypes and two influenza B lineages. After intramuscular or subcutaneous injection, the antigens are taken up by antigen‑presenting cells, which process and display viral proteins to T‑lymphocytes. This triggers a humoral immune response, leading to the production of strain‑specific neutralizing antibodies that confer protection against subsequent exposure to the matched influenza viruses.

Like other inactivated influenza vaccines, Influvac Tetra may be associated with local and systemic reactions.

Common Side Effects

• Injection site pain: mild to moderate discomfort at the injection site.
• Redness or swelling: localized erythema or edema around the injection area.
• Low‑grade fever: transient temperature rise, usually ≤38.5 °C.
• Headache: mild headache occurring within 24 hours post‑vaccination.
• Myalgia: muscle aches that resolve spontaneously.

Serious or Rare Side Effects

• Anaphylaxis: severe allergic reaction requiring immediate medical attention.
• Guillain‑Barré syndrome: rare neurological disorder potentially linked to vaccination.
• Seizures: infrequent occurrence, particularly in children with fever.
• Thrombocytopenia: low platelet count observed rarely after vaccination.

Prior to administering Influvac Tetra, healthcare professionals should observe the following precautions.

• Allergy assessment: avoid use in individuals with a known severe allergy to any vaccine component.
• Fever evaluation: defer vaccination if the recipient has a moderate or high fever at the time of injection.
• Recent vaccine history: postpone administration if another vaccine was given within 14 days to reduce reactogenicity.
• Immunocompromised status: consider reduced immunogenicity in patients with severe immunosuppression.
• Pregnancy and lactation: assess risk‑benefit; data are limited, so use only if clearly indicated.
• Store at 2‑8 °C: keep refrigerated, protect from light, do not freeze or shake.

Influvac Tetra may interact with certain medical products; awareness of these interactions helps ensure safe vaccination.

Major Interactions (Avoid)

• Live attenuated vaccines: avoid co‑administration within 4 weeks to prevent interference with immune response.
• Immunoglobulin therapy: concurrent administration may diminish vaccine efficacy.
• Antiviral medications: avoid within 48 hours before or after vaccination as they may affect antibody development.

Moderate Interactions (Monitor Closely)

• Other injectable vaccines: simultaneous injection may increase local reactogenicity; monitor injection sites.
• Antipyretics: prophylactic use may blunt antibody response; advise use only after vaccination if needed.
• Corticosteroids: high‑dose systemic steroids may reduce immunogenicity; assess timing relative to vaccination.