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 prevent seasonal influenza infection.

• Seasonal influenza: reduces the risk of infection and related complications in the general population.
• Elderly individuals: helps lower the incidence of severe flu outcomes in people aged 65 and older.
• Children and adolescents: provides protection against circulating influenza strains in younger age groups.

• Influvac Tetra contains inactivated influenza virus antigens that are recognized by the immune system. Upon intramuscular or subcutaneous injection, the antigens stimulate B‑cell production of strain‑specific antibodies and activate T‑cell responses, establishing active immunity that neutralizes the corresponding influenza viruses upon exposure.

Common side effects are generally mild and transient, reflecting the body's immune response to the vaccine.

Common Side Effects

• Injection site pain: mild to moderate discomfort at the injection site.
• Redness or swelling: localized erythema or edema.
• Low‑grade fever: temperature elevation up to 38°C.
• Headache: mild to moderate intensity.
• Fatigue or malaise: general feeling of tiredness.
• Muscle aches: transient myalgia.

Serious or Rare Side Effects

• Anaphylaxis: severe allergic reaction requiring immediate medical attention.
• Guillain‑Barré syndrome: rare neurological disorder with muscle weakness.
• Seizures: uncommon neurologic event.
• High fever: temperature above 39°C persisting more than 24 hours.
• Severe local reaction: extensive swelling or necrosis at injection site.
• Thrombocytopenia: low platelet count observed in rare cases.

Before administering Influvac Tetra, consider the following precautions.

• Allergy screening: avoid use in individuals with known hypersensitivity to any vaccine component.
• Acute illness: defer vaccination in persons with moderate or severe acute febrile illness.
• Immunocompromised patients: vaccine may be less effective; assess risk‑benefit.
• Egg allergy: evaluate severity; vaccine may be used with caution in mild egg‑allergic individuals.
• Pregnancy and lactation: consult healthcare provider; safety data are limited.
• Store at 2-8°C: keep refrigerated, protect from light, do not freeze or shake.

Influvac Tetra may interact with other medical interventions; monitor accordingly.

Major Interactions (Avoid)

• Severe egg protein allergy: contraindicated due to potential hypersensitivity.
• History of Guillain‑Barré syndrome following prior influenza vaccination: avoid repeat dosing.

Moderate Interactions (Monitor Closely)

• Immunosuppressive therapy: may reduce vaccine efficacy; consider timing.
• Antipyretics (e.g., acetaminophen) taken prophylactically: could blunt antibody response.
• Live vaccines administered concurrently: generally safe but schedule spacing may be advised.
• Antiviral medications (e.g., oseltamivir) started shortly before vaccination: may affect immune response.
• Blood products or immunoglobulins given within 3 months: could interfere with vaccine‑induced immunity.