Specific vaccination recommendations vary among countries or even within a given country. Local or country-specific guidelines should be consulted.
1. Vaccines: There are 3 vaccines currently authorized for use in Canada: the Salmonella enterica serovar Typhi Vi capsular polysaccharide vaccine (Typh-I); the purified Vi polysaccharide vaccine combined with inactivated hepatitis A vaccine (HA-Typh-I); and the live, oral, attenuated TY21A vaccine (Typh-O).
2. Indications: Vaccination is recommended in travelers to rural areas with poor sanitation in low-income countries that are endemic for S enterica serovar Typhi, as well as countries where resistant strains of S enterica serovar Typhi are found (ie, sub-Saharan Africa, North Africa, South and Southeast Asia, Middle East, South America). The risk of typhoid fever is currently highest in India, Pakistan, and Bangladesh. Vaccination is also recommended in travelers to endemic areas with functional or anatomic asplenia or with achlorhydria.
Immunization is also recommended for individuals with ongoing or intimate exposure to a chronic carrier of S enterica serovar Typhi.
3. Contraindications include general contraindications for all vaccines, such as hypersensitivity or anaphylactic reaction to any vaccine component. In addition, the Typh-O vaccine is contraindicated in those with an acute gastrointestinal illness, inflammatory bowel disease, or immunocompromise (eg, persons with HIV). There are no safety data for pregnant or breastfeeding women.
The Typh-O vaccine should not be administered while the patient is receiving sulfonamide antibiotics or antimalarials (except chloroquine, mefloquine, and atovaquone/proguanil), as these medications can affect vaccine efficacy.
4. Adult immunization schedule:
1) Typh-I and HA-Typh-I vaccines: Primary vaccination is a single dose of 0.5 mL IM administered ≥14 days prior to travel. Individuals at continued risk of S enterica serovar Typhi infection should be vaccinated every 3 years. For the combined HA-Typh-I vaccine, a single dose of hepatitis A vaccine should be given 6 to 36 months later. Individuals at continued risk of S enterica serovar Typhi infection may receive Typh-I or HA-Typh-I after 3 years following completion of the primary series.
2) Typh-O vaccine: Primary vaccination is 1 capsule administered orally on days 1, 3, 5, and 7 (4 doses). The immunization series should be completed ≥1 week before travel and should be taken ~1 hour prior to or 2 hours after a meal. Patients should refrain from consuming alcoholic beverages 1 hour prior to or 2 hours after administration of a dose of oral vaccine. Individuals at continued risk of S enterica serovar Typhi infection should repeat the primary Typh-O vaccine series every 7 years.
In the event that a person is receiving a cholera vaccine and oral typhoid vaccine prior to travel to an endemic area, administration of these vaccines should be ≥8 hours apart.
5. Adverse events:
1) Typh-I and HA-Typh-I vaccines: Local injection site reaction, fever, headache, malaise, myalgia occur in 1% to 10% of vaccine recipients.
2) Typh-O vaccine: Abdominal pain, nausea, diarrhea, vomiting, fever, headache, or rash occur in 1% to 10% of vaccine recipients.