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

Influvac Tetra is a quadrivalent influenza vaccine used to protect against seasonal influenza viruses.

• Seasonal influenza (all ages): induces immunity against the four virus strains contained in the vaccine, reducing the risk of infection.
• High‑risk groups (elderly, chronic disease patients): lowers the incidence of severe flu‑related complications.
• Pregnant women (second and third trimester): helps protect both mother and newborn from influenza infection.

• Influvac Tetra contains inactivated virus particles from four influenza strains. After intramuscular or subcutaneous injection, the vaccine antigens are taken up by antigen‑presenting cells, which stimulate B‑cell production of strain‑specific antibodies and activate T‑cell responses, establishing active immunity that neutralises the corresponding influenza viruses upon exposure.

Influvac Tetra may cause local and systemic reactions following injection.

Common Side Effects

• Injection site pain: mild to moderate discomfort at the injection site.
• Redness or swelling: transient erythema and edema around the site.
• Low‑grade fever: temporary rise in body temperature.
• Headache: mild to moderate headache within 24‑48 hours.
• Myalgia: muscle aches that resolve spontaneously.
• Fatigue: short‑term tiredness after vaccination.

Serious or Rare Side Effects

• Anaphylaxis: severe allergic reaction requiring immediate medical attention.
• Guillain‑Barré syndrome: rare neurological disorder that may develop weeks after vaccination.
• Seizures: infrequent occurrence, especially in children with a history of febrile seizures.
• Severe allergic reaction: hives, swelling of the face or throat.
• High‑grade fever: persistent fever above 39°C.
• Thrombocytopenia: rare drop in platelet count.

Before administering Influvac Tetra, consider the following precautions.

• Allergy assessment: avoid use in individuals with known severe allergy to any vaccine component.
• Egg allergy: evaluate risk in patients with severe egg allergy; consult guidelines.
• Immunocompromised patients: vaccine may be less effective; monitor immune response.
• Acute illness: defer vaccination until the patient recovers from moderate or severe acute illness.
• Pregnancy and lactation: use only if benefits outweigh potential risks; discuss with healthcare provider.
• Storage: Store at 2‑8 °C: keep refrigerated, protect from light, do not freeze or shake.

Influvac Tetra may interact with other therapies that affect immune function.

Major Interactions (Avoid)

• Immunosuppressive therapy: may markedly reduce vaccine efficacy.
• Live viral vaccines administered concurrently: may interfere with immune response; schedule appropriately.

Moderate Interactions (Monitor Closely)

• Antipyretics (acetaminophen, ibuprofen) taken prophylactically: may blunt antibody response.
• Blood products or immunoglobulins given within 3 months: could diminish vaccine‑induced immunity.
• Antiviral medications (e.g., oseltamivir) started shortly before or after vaccination: may affect immune response.
• Corticosteroids at high doses: may reduce immunogenicity.
• Other inactivated vaccines given simultaneously: generally safe but monitor for additive local reactions.