Neisvac-C (N. Meningitidis Group C (Strain C11) Polysaccharide (De-O-Acetylated) Conjugated To Tetanus Toxoid)

Neisvac‑C is a conjugate vaccine targeting Neisseria meningitidis serogroup C, used to prevent invasive meningococcal disease.

• Prevention of invasive disease caused by Neisseria meningitidis serogroup C: provides active immunity that reduces the risk of meningitis and septicemia in at‑risk individuals.
• Outbreak control: employed in mass vaccination campaigns to rapidly curb serogroup C meningococcal outbreaks.
• Routine immunisation: incorporated into national immunisation schedules for adolescents to maintain herd immunity against serogroup C.

• The vaccine contains polysaccharide from N. meningitidis group C chemically linked to tetanus toxoid, creating a conjugate that is recognized by the immune system as a protein antigen. This conjugation enables T‑cell dependent activation of B cells, leading to robust production of high‑affinity anti‑capsular antibodies and immunological memory, thereby providing long‑lasting protection against serogroup C meningococcal infection. The conjugate also facilitates affinity maturation and class switching, enhancing the quality of the antibody response.

Neisvac‑C, like other conjugate vaccines, may be associated with local and systemic reactions following intramuscular administration.

Common Side Effects

• Injection site pain: mild to moderate soreness at the injection site.
• Redness or swelling: transient erythema or edema at the site.
• Fever: low‑grade temperature rise within 24 hours.
• Headache: mild headache reported in some recipients.

Serious or Rare Side Effects

• Anaphylaxis: severe allergic reaction requiring immediate medical attention.
• Guillain‑Barré syndrome: rare demyelinating neuropathy reported post‑vaccination.
• Seizure: occasional febrile seizure in children.
• Hypotension: sudden drop in blood pressure after injection.

Prior to administering Neisvac‑C, healthcare professionals should observe specific precautions to minimise risk and ensure optimal vaccine performance.

• Screen for hypersensitivity: avoid vaccination in individuals with known allergy to any vaccine component.
• Defer in acute illness: postpone administration if the recipient has moderate or severe fever or infection.
• Post‑vaccination observation: monitor the patient for at least 15 minutes for signs of anaphylaxis.
• Live vaccine co‑administration: separate from live attenuated vaccines unless guidelines permit simultaneous use.
• Pregnancy and lactation: vaccinate only if the expected benefit outweighs potential risk, after clinical assessment.
• Store at 2‑8 °C: keep refrigerated, protect from light, do not freeze or shake.

Neisvac‑C may interact with other medicines or biologics, influencing immune response or safety.

Major Interactions (Avoid)

• Live attenuated vaccines: concurrent use may reduce efficacy of either vaccine; schedule separately.
• Immunoglobulins or blood products: may neutralise the vaccine antigen and diminish immune response.
• Immunosuppressive therapy: high‑dose steroids or chemotherapy can impair antibody production after vaccination.

Moderate Interactions (Monitor Closely)

• Antipyretics: may mask post‑vaccination fever, making assessment of reaction more difficult.
• Antibiotics: generally do not affect vaccine efficacy, but monitor for allergic cross‑reactivity if penicillin is involved.
• Antihistamines: may conceal early signs of an allergic reaction; observe patient closely.