Vaxphoid25 mcg/0.5 ml

Vaxphoid is indicated for active immunization against typhoid fever caused by Salmonella enterica serotype Typhi in individuals 2 years of age and older.

• Established/approved use: Primary immunization of travelers to regions where typhoid fever is endemic, particularly areas with recognized risk of exposure to S. Typhi.
• Established/approved use: Immunization of individuals with ongoing household or intimate exposure to a documented S. Typhi carrier.
• Established/approved use: Immunization of laboratory personnel who routinely work with S. Typhi cultures.
• Guideline-supported use: Use in populations residing in or relocating to areas of poor sanitation or unsafe water/food supply where typhoid is endemic, per national and international immunization recommendations.

Vaxphoid does not protect against typhoid caused by Salmonella Paratyphi and does not replace standard food and water safety precautions.

Each 0.5 mL dose of Typhoid Polysaccharide Vaccine contains purified Vi capsular polysaccharide antigen (approximately 25 micrograms) extracted from Salmonella enterica serotype Typhi (Ty2 strain), in an isotonic buffered saline solution containing phenol as a preservative.

Vaxphoid is a sterile, purified preparation of the Vi capsular polysaccharide antigen obtained from the cell wall of Salmonella Typhi bacteria. It is an inactivated (non-live), subunit vaccine supplied as a clear, colorless liquid for intramuscular injection. Unlike the live attenuated oral typhoid vaccine, Vaxphoid contains no live organisms and cannot cause typhoid infection.

Vaxphoid belongs to the therapeutic class of bacterial polysaccharide vaccines, specifically inactivated (subunit) vaccines used for active immunization against typhoid fever.

Typhoid Polysaccharide Vaccine works by inducing a T-cell independent humoral immune response against the Vi capsular polysaccharide antigen present on the surface of Salmonella Typhi. Following intramuscular administration, the immune system produces anti-Vi antibodies that help protect against invasive typhoid infection by targeting the bacterial capsule.

A protective antibody response typically develops within 1-2 weeks after a single dose of Typhoid Polysaccharide Vaccine and provides protection for approximately 2-3 years, after which a booster dose is required to maintain immunity in individuals with continued exposure risk. Because the Vi polysaccharide antigen does not reliably stimulate immune memory in children younger than 2 years, Typhoid Polysaccharide Vaccine is not recommended for this age group.

Vaxphoid must be administered only by intramuscular injection, preferably into the deltoid muscle. It should be given at least 2 weeks prior to expected exposure to allow adequate time for a protective antibody response to develop. Do not inject intravenously, intradermally, or subcutaneously. Use a separate sterile syringe and needle for each individual to prevent transmission of infectious agents.

Vaxphoid can generally be administered concomitantly with other vaccines (e.g., hepatitis A vaccine, yellow fever vaccine) at separate injection sites, based on available clinical data.

• Immunosuppressive therapy/immunosuppression: Concurrent use of corticosteroids, chemotherapy, radiation therapy, or other immunosuppressive treatments may reduce the immune response to Vaxphoid; vaccination should ideally be completed before starting such therapy, where possible.
• Antimalarial agents (e.g., mefloquine, chloroquine): No clinically significant interference with the immune response to Vaxphoid has been established; co-administration is generally considered acceptable.

Side effects of Vaxphoid are generally mild and self-limited.

• Very common: Injection site pain, tenderness, redness, or induration.
• Common: Fever, headache, malaise, fatigue, myalgia.
• Uncommon: Nausea, gastrointestinal upset, rash, pruritus.
• Rare: Hypersensitivity reactions, including anaphylaxis (see Contraindications).

Most reactions to Vaxphoid resolve within 1-2 days without treatment.

Adequate and well-controlled studies of Vaxphoid in pregnant women are lacking. Vaxphoid should be used during pregnancy only if clearly needed and the potential benefit justifies the potential risk to the fetus; a physician should be consulted to weigh the risk of typhoid exposure against theoretical vaccine risk.

It is not known whether Vaxphoid is excreted in human milk. Caution should be exercised when administering Vaxphoid to a breastfeeding woman, and a physician should be consulted before use.

Vaxphoid provides protection against typhoid fever starting approximately 1-2 weeks after vaccination; it does not offer immediate protection and does not protect against Salmonella Paratyphi (paratyphoid fever).

• Vaccination with Vaxphoid does not eliminate the need for continued food and water safety precautions in endemic areas.
• As with any vaccine, appropriate medical treatment and supervision should be available in case of a rare anaphylactic reaction following administration of Vaxphoid.
• Individuals with impaired immune responsiveness (e.g., due to HIV infection or immunosuppressive therapy) may have a diminished antibody response to Vaxphoid.
• Protection wanes over time; a booster dose of Vaxphoid is required every 2-3 years for individuals with continued exposure risk.

There is no clinical experience with overdose of Vaxphoid, as it is administered as a single-dose injection by a healthcare professional. If an inadvertent excess dose or repeat dose is given, or if a severe reaction occurs after administration of Vaxphoid, seek immediate medical attention or contact emergency services / a poison control center.

Vaxphoid should be stored refrigerated at 2°C to 8°C (36°F to 46°F). Do not freeze; discard if the vaccine has been frozen. Protect from light. Keep out of reach of children.

Renal/hepatic impairment: No specific dose adjustment of Vaxphoid is established; use per standard clinical judgment.

Elderly: Vaxphoid may be used in elderly individuals at risk of typhoid exposure; clinical experience in this population is limited.

Immunocompromised individuals: May have a reduced immune response to Vaxphoid (see Precautions and Warnings).

Pregnancy and lactation: See Pregnancy and Lactation section.

Vaxphoid is given as a single primary dose, with a booster dose recommended every 2-3 years for individuals who remain at continued or repeated risk of typhoid exposure. The duration of protective immunity following Vaxphoid is approximately 2-3 years.

Typhoid Polysaccharide Vaccine is classified as a bacterial capsular polysaccharide vaccine (inactivated/subunit vaccine).

Typhoid Polysaccharide Vaccine contains purified Vi capsular polysaccharide antigen from Salmonella Typhi. After intramuscular injection, the antigen stimulates B-lymphocytes to produce anti-Vi IgG antibodies through a T-cell independent pathway. These antibodies help opsonize and neutralize S. Typhi bacteria bearing the Vi antigen, reducing the risk of invasive typhoid infection.

Vaxphoid is approved for use in children 2 years of age and older, at the same 0.5 mL single intramuscular dose used in adults.

Vaxphoid is not recommended for children younger than 2 years, as the polysaccharide antigen does not reliably produce a protective immune response in this age group; safety and efficacy of Vaxphoid in infants under 2 years have not been established.