Infanrix Tetra (Diphtheria Toxoid, Tetanus Toxoid, Pertussis Toxoid, Pertussis Filamentous Haemagglutinin, Pertussis)

Infanrix Tetra is a diphtheria‑tetanus‑acellular pertussis (DTaP) vaccine used to actively immunise against bacterial toxin‑mediated diseases in early childhood.

• Diphtheria: provides protective immunity that reduces the risk of severe respiratory disease in infants and children.
• Tetanus: induces antibodies that prevent tetanus toxin‑mediated muscle rigidity and spasms in the pediatric population.
• Pertussis (whooping cough): stimulates immune response against pertussis toxin and related antigens, decreasing incidence and severity of cough in young children.

• Infanrix Tetra contains purified diphtheria toxoid, tetanus toxoid and acellular pertussis antigens (pertussis toxin, filamentous haemagglutinin and pertactin) adsorbed onto an aluminium‑based adjuvant. After intramuscular injection, the toxoids are recognized as foreign, prompting B‑cell activation and production of specific antibodies. The pertussis antigens similarly elicit a humoral and cellular immune response, establishing immunological memory that protects against subsequent exposure to the respective bacteria.

Infanrix Tetra, like other injectable vaccines, may be associated with local and systemic reactions following administration.

Common Side Effects

• Injection site pain: mild to moderate discomfort at the injection site.
• Redness or swelling: localized erythema or edema that resolves within a few days.
• Fever: low‑grade temperature elevation occurring within 24‑48 hours.
• Irritability: temporary fussiness or crying in infants.
• Loss of appetite: brief reduction in feeding.

Serious or Rare Side Effects

• Severe allergic reaction: anaphylaxis characterized by airway swelling, hives, or hypotension.
• Seizures: rare febrile convulsions following high fever.
• Persistent high fever: prolonged temperature above 40 °C requiring medical attention.
• Neurological complications: rare cases of encephalopathy reported post‑vaccination.

Before administering Infanrix Tetra, healthcare professionals should observe several precautionary measures to ensure safety and vaccine efficacy.

• Contraindication: avoid use in individuals with a known severe allergy to any vaccine component.
• Prior reaction: postpone vaccination if the child experienced a serious reaction to a previous DTaP dose.
• Illness: defer administration during moderate or severe acute illness with fever.
• Immunocompromised: assess risk‑benefit in patients with severe immunodeficiency, as response may be reduced.
• Pregnancy: vaccine is not routinely recommended for pregnant women; consult guidelines before use.
• Store at 2-8°C: keep refrigerated, protect from light, do not freeze or shake.

Infanrix Tetra has limited drug‑interaction potential, but certain concomitant therapies may affect its safety or immunogenicity.

Major Interactions (Avoid)

• Live vaccines: avoid administering other live attenuated vaccines within 4 weeks before or after Infanrix Tetra to prevent interference.
• Immunoglobulin therapy: concurrent IVIG may diminish antibody response to the vaccine.

Moderate Interactions (Monitor Closely)

• Antipyretics: prophylactic use of acetaminophen or ibuprofen may reduce antibody titres; consider timing after vaccination.
• Corticosteroids: high‑dose systemic steroids may blunt immune response, requiring assessment.
• Immunosuppressants: agents such as methotrexate may lower vaccine efficacy and should be evaluated.