TYPHOID VACCINE – POLYSACCHARIDE VI ANTIGEN VACCINE
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.
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.
- Age less than 2 years
- 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).