Influvac (Influenza Virus B/Austria/1359417/2021-Like Strain (B/Austria/1359417/2021, Bvr-26), Influenza A/Vic)

Influvac is a seasonal influenza vaccine used to prevent infection by influenza A and B viruses.

• Seasonal influenza prevention: provides active immunity against circulating influenza A (including A/Vic) and B (including B/Austria/1359417/2021‑like) strains.
• High‑risk population protection: reduces the incidence of flu in elderly, immunocompromised, or individuals with chronic medical conditions.
• Public health immunisation: contributes to community‑level protection during annual influenza seasons.

• Influvac contains inactivated influenza virus antigens that are recognized by the host immune system. Upon intramuscular or subcutaneous injection, antigen‑presenting cells process the viral proteins and stimulate B‑cell and T‑cell responses, leading to the production of strain‑specific antibodies that neutralise influenza A and B viruses upon subsequent exposure.

Common Side Effects

• Injection site pain: mild to moderate soreness at the injection site.
• Redness or swelling: localized erythema or edema.
• Low‑grade fever: transient temperature rise within 24‑48 hours.
• Headache or myalgia: mild headache or muscle aches.
• Fatigue: temporary feeling of tiredness.

Serious or Rare Side Effects

• Anaphylaxis: severe allergic reaction requiring immediate medical attention.
• Guillain‑Barré syndrome: rare neurological disorder with muscle weakness.
• Seizures: infrequent occurrence, especially in individuals with a history of seizures.
• Severe allergic reaction: hives, swelling of face or throat, difficulty breathing.

Before receiving Influvac, consider the following precautions.

• Allergy assessment: avoid if there is a known severe allergy to any vaccine component.
• Guillain‑Barré history: consult a healthcare professional if the individual has previously experienced Guillain‑Barré syndrome.
• Pregnancy considerations: discuss vaccination with a physician to weigh benefits and risks.
• Immunocompromised status: vaccine may be less effective; monitor immune response.
• Age limitation: not recommended for children younger than six months.
• Store at 2-8°C: keep refrigerated, protect from light, do not freeze or shake.

Influvac may interact with other medical products; monitor as indicated.

Major Interactions (Avoid)

• Concurrent administration of blood products or immunoglobulins: may diminish vaccine efficacy.
• Live attenuated vaccines given within 4 weeks: could interfere with immune response.

Moderate Interactions (Monitor Closely)

• Immunosuppressive therapy (e.g., corticosteroids, chemotherapy): may reduce antibody production.
• Antipyretic or analgesic use before vaccination: can mask early signs of adverse reactions.
• Antiviral medications (e.g., oseltamivir) started shortly after vaccination: may affect immune response.
• Seasonal influenza prophylaxis agents: coordinate timing to avoid overlapping immune stimulation.