Typhoid polysaccharide vaccine

• Prevention of typhoid fever: Active immunization against Salmonella enterica serotype Typhi, the bacterium causing typhoid fever.
• Approved for:
• Individuals aged 2 years and older who are at increased risk of exposure to typhoid fever in endemic areas or travelers to endemic regions.
• Off-label/clinical uses:
• Used in outbreak control to reduce disease spread.
• Booster doses in at-risk populations to maintain protective immunity.

• Standard dose: Single dose of 0.5 mL administered via intramuscular (preferred) or subcutaneous injection.
• Age considerations: Recommended for persons aged 2 years and above; not indicated for children under 2 due to insufficient immunogenicity.
• Booster dose: Recommended every 2 years for individuals continuing to be at risk.
• Route: Intramuscular injection, usually in the deltoid muscle; subcutaneous administration acceptable if necessary.
• Special populations: No specific dose adjustments are required for elderly, renal impairment, or hepatic impairment. Immunocompromised patients may have reduced vaccine response but vaccination is still advised.

The typhoid polysaccharide vaccine contains purified Vi capsular polysaccharide antigen from Salmonella Typhi. It induces a T-cell independent immune response, primarily activating B lymphocytes to produce specific anti-Vi IgG antibodies. These antibodies bind the bacterial capsule, facilitating opsonization and clearance of Salmonella Typhi, thus preventing systemic infection. However, this mechanism results in limited immunologic memory and suboptimal responses in children under 2 years.

Not applicable as the vaccine’s action is mediated by the immune system rather than systemic absorption, metabolism, or elimination.

• Pregnancy: Limited human data; generally considered low risk as it contains no live organisms. Use only if clearly needed.
• Lactation: No specific data; considered safe because vaccine components are unlikely to be excreted into breast milk or affect the infant.

• Primary class: Vaccine
• Subclass: Polysaccharide vaccine (non-conjugated)
• Generation: First-generation typhoid vaccine

• Known hypersensitivity to any component of the vaccine.
• Severe acute illness with or without fever (vaccination deferred until recovery).
• History of severe allergic reaction to prior doses of typhoid polysaccharide vaccine.

• May cause local injection site reactions.
• Immunocompromised individuals may have diminished immune response.
• Vaccination does not protect against paratyphoid fever or other non-typhoidal Salmonella infections.
• Immunity is not lifelong; booster doses are necessary.
• Vaccination should complement, not replace, appropriate sanitary and hygiene practices.

• Common: Injection site pain, redness, swelling; mild fever; headache; malaise.
• Less common: Fatigue, muscle aches.
• Rare: Severe allergic reactions such as anaphylaxis, urticaria, or angioedema.

• No significant interactions with drugs, food, or alcohol identified.
• May be administered concomitantly with other vaccines but at different injection sites.

• WHO recommends typhoid polysaccharide vaccine for travelers and outbreak control where conjugate vaccines are unavailable.
• Typhoid conjugate vaccines are preferred for young children and provide longer-lasting immunity.
• Updated guidelines emphasize integrating vaccination with water and sanitation improvements in endemic regions.

• Store refrigerated at 2°C to 8°C (36°F to 46°F).
• Protect from freezing and light exposure.
• Use before the expiration date printed on the packaging.