Polysaccharide VI Antigen Vaccine

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It is the most common type of typhoid vaccine being used.

Type of vaccine

  • It is prepared from VI antigen of the outer covering (capsule) of bacteria which cause typhoid fever.
  • It is available as an injection containing 25µg per dose.
  • It is effective only after 2 years of age.
  • Immunity develops 7 – 15 days after injection and protection lasts for 3 years.
  • The efficacy is around 70%.  However, it does not give protection against paratyphoid fever (A and B).

Dosage & schedule

  • This vaccine is usually administered around 3 years of age.
  • Single dose 0.5 ml (25µg) deep subcutaneous (SC) orIntramuscular (IM).
  • Booster dose is given every 3 years.

Side effects

All are mild and self-limiting.

  • Local pain, rash and swelling at the site of injection.
  • Rarely mild fever.


  • Children with a history of allergic or severe reaction following the previous dose.
  • Pregnancy
  • Age less than 2 years

Special precautions

  • It is preferable to delay the vaccine in high fever and acute infection
  • It must be remembered that this vaccine does not confer protection against Paratyphoid fever (type A and B).