typhoid, combinations with paratyphi types

J07AP10

Forms & Strengths

Injectable suspension (Typhoid Vi polysaccharide vaccine): 0.5 mL per prefilled syringe or single-dose vial
Oral capsules (Live attenuated Ty21a vaccine): 2 billion viable cells per enteric-coated capsule

Adult Dosing

Injectable: 0.5 mL intramuscularly single dose, administered at least 2 weeks prior to potential exposure; revaccination every 2 years for continued exposure risk
Oral: One capsule taken on alternate days (days 1, 3, 5, and 7) for a total of 4 capsules, completed at least 1 week prior to travel; revaccination with the full 4-dose series every 5 years

Pediatric Dosing

Injectable (children >= 2 years): 0.5 mL intramuscularly single dose; revaccination every 2 years if exposure risk persists
Oral (children >= 6 years): One capsule on alternate days (days 1, 3, 5, and 7) for a total of 4 capsules; revaccination every 5 years

Indications

Active immunization against infection caused by Salmonella typhi (typhoid fever)
Travelers, laboratory personnel, and household contacts of chronic carriers at high risk of exposure

Mechanism of Action

Typhoid Vi polysaccharide vaccine stimulates antibody production against the Vi capsular polysaccharide of Salmonella typhi
Ty21a oral vaccine provides live attenuated Salmonella typhi Ty21a bacteria, inducing humoral and cell-mediated immune responses in the intestinal mucosa and systemic circulation

Contraindications

History of severe allergic reaction (e.g., anaphylaxis) to any component of the vaccine
Oral Ty21a: Contraindicated in immunocompromised individuals (congenital or acquired immunodeficiencies, immunosuppressive therapy) and acute febrile illness or acute gastrointestinal illness

Adverse Reactions

Injection site pain, erythema, and swelling
Fever, headache, malaise, and myalgia
Oral formulation: Mild gastrointestinal symptoms including abdominal discomfort, nausea, vomiting, diarrhea, and rash

Drug Interactions

Antibacterial agents (oral Ty21a): Concomitant administration of antibiotics may interfere with the viability of the live attenuated vaccine strain; avoid use during or shortly after systemic antibiotic therapy
Immunosuppressive therapies: May blunt the immune response to both injectable and oral vaccines
Other live vaccines: Oral Ty21a can be administered concurrently with other live viral vaccines (e.g., yellow fever, oral polio) or separated by at least 4 weeks if interference is suspected

Curated Content: Needs Vetting Before Put to Clinical Use