Typhim Vi (typhoid vaccine VI capsular polysaccharide)

Typhoid Vaccine Intramuscular Syringe (ML); Intramuscular Vial (ML)

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Last reviewed · Source: First Databank (FDB) drug data

Overview

Typhoid vaccine is available as an oral live, attenuated vaccine (typhoid vaccine live oral Ty21a; Vivotif(R)) and a parenteral inactivated Vi polysaccharide vaccine (typhoid Vi polysaccharide vaccine; Typhim Vi(R)).

Typhoid vaccines stimulate active immunity to typhoid fever in individuals at high risk of exposure to Salmonella enterica serovar Typhi.

Response to Typhoid Vaccine Live Oral Ty21a

The exact mechanism by which typhoid vaccine live oral Ty21a elicits an immune response is not known; however, the oral vaccine is thought to produce a local immune response in the GI tract. Seroconversion rates in healthy US adults following primary immunization with 3 doses of typhoid vaccine live oral Ty21a are similar to those attained in residents of typhoid-endemic areas. Following ingestion, virulent strains of Salmonella Typhi can pass through the stomach acid barrier, colonize the intestinal tract, penetrate the intestinal lumen, and enter the lymphatic system and blood stream, resulting in infection.

It has been suggested that oral administration of typhoid vaccine containing a live, attenuated strain of the bacilli may elicit a local immune response in the intestinal tract while undergoing an aborted infection, with resultant protection against subsequent infection with a virulent strain. However, the ability of Salmonella Typhi to elicit a protective immune response depends on possession by the bacilli of a complete lipopolysaccharide. The ability of the live, attenuated strain present in the oral typhoid vaccine to produce a complete lipopolysaccharide is limited since this strain is deficient in enzymes essential for lipopolysaccharide biosynthesis; however, sufficient complete lipopolysaccharide apparently is produced to elicit an adequate immune response.

In addition, despite low levels of lipopolysaccharide biosynthesis by the vaccine strain, sufficient quantities of intermediates of this synthesis accumulate and induce cell lysis before the organism can gain a virulent phenotype.

In a series of field trials in Chile, efficacy of the live, attenuated vaccine (as enteric-coated capsules) given as a 1- or 2-dose regimen in school-aged children was 21 or 54%, respectively, after 33 months of surveillance. When a 3-dose regimen (as enteric-coated capsules) was administered on alternate days (short-schedule immunization) or 21 days apart (long-schedule immunization) in Chilean school-age children, vaccine efficacy was 67 or 49%, respectively, after 36 months of surveillance; after 48 months, efficacy of the short-schedule immunization was 69%. The level of immune protection was undiminished during the fifth year of surveillance.

Experience in individuals from areas without endemic disease (e.g., US residents) who travel to endemic regions also is limited, but seroconversion rates reported following a 3-dose primary immunization series with the live, attenuated vaccine in such individuals are comparable to those in residents of endemic areas. Because of the low incidence of typhoid fever in the US, efficacy studies are not possible in this population; however, evidence from antibody-titer studies suggests that the live, attenuated vaccine will provide protection to vaccine recipients residing in nonendemic areas such as the US. The duration of response after primary immunization with typhoid vaccine live oral Ty21a has not been established.

Response to Typhoid Vi Polysaccharide Vaccine

Administration of typhoid Vi polysaccharide vaccine stimulates immunity to Salmonella Typhi by inducing production of antibodies to the Vi antigen. Antibodies to the Vi antigen confer protection against typhoid fever. IM administration of a single dose of typhoid Vi polysaccharide vaccine in most healthy adults and children 2 years of age or older generally results in a 4-fold or greater increase in serum antibodies specific for the Vi antigen within 4 weeks.

Results of several US studies indicate that a single 25-mcg dose of Vi polysaccharide vaccine results in a 4-fold or greater increase in serum antibodies in 88-96% of healthy adults. Because baseline antibody titers from individuals from typhoid-endemic areas (i.e., Nepal, South Africa, Indonesia) indicate prior exposure to Salmonella Typhi, vaccine-induced antibody response in these individuals differs from that produced in ''typhoid naive'' populations (e.g., most travelers from the US). In studies conducted in Nepal, administration of a single 25-mcg dose of typhoid Vi polysaccharide vaccine in children 5-14 years of age, adolescents and adults 15-44 years of age, or adults 45-55 years of age produced a 4-fold or greater increase in antibody titers within 4 weeks in approximately 77, 79, or 63% of individuals, respectively.

A single 25-mcg dose of the vaccine produced a 4-fold or greater increase in serum antibodies within 4 weeks in about 96% of Indonesian children aged 2-5 years of age. The titer of antibody that is protective against typhoid has not been determined to date.

Limited evidence indicates that antibody titers against the Vi antigen remain elevated for at least 12 months following administration of typhoid Vi polysaccharide vaccine in children 5-15 years of age residing in typhoid-endemic areas and for at least 36 months in healthy US adults. Administration of an additional dose of typhoid Vi polysaccharide vaccine in healthy US adults 27-34 months after the initial dose produces antibody titers comparable to those obtained following the primary dose.

Efficacy of a single 25-mcg dose of typhoid Vi polysaccharide vaccine in preventing typhoid fever has been demonstrated in a series of field trials in typhoid-endemic areas. In a trial in Nepal in individuals 5-44 years of age, those who received the vaccine had 74% fewer cases of culture-confirmed Salmonella Typhi infection over a 20-month period follow-up period. Surveillance in immunized South African children indicated that vaccine efficacy was 61, 52, or 50% after 1, 2, or 3 years; overall vaccine efficacy was 55%.

USES: This vaccine is used to help prevent typhoid fever. Typhoid fever is an infection that can be spread by eating contaminated food or drinking contaminated water. This vaccine works by increasing the body's natural defense (immunity) against the bacteria.

This vaccine is recommended for people who are traveling to areas where the infection is common (such as Africa, Asia, Central/South America), those who are in close contact to someone with an ongoing typhoid infection, and those who work with the bacteria (Salmonella typhi) in a lab. Vaccines may not fully protect everyone who receives them.

Generic name: typhoid vaccine VI capsular polysaccharide
Drug class: Typhoid Vaccine
Therapeutic class: Biologicals

Reference product & biosimilars

No reference, biosimilar or interchangeable associated with this drug.

Today’s intelligence on Typhim Vi

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Indications

The following indications are listed for Typhim Vi:

  • Typhoid Vaccination

Also known as: Active Immunization Against Salmonella Typhi, Active Immunization For The Prevention Of Typhoid Fever, Typhoid Prevention.

Dosing

Dosing schedules (i.e., number of doses, timing prior to potential exposure to typhoid fever) differ between typhoid vaccine live oral Ty21a and typhoid Vi polysaccharide vaccine. Dosage recommendations for the specific preparation used should be followed.

Drug interactions

There is no enhanced messaging for this drug.

Contraindications

*Typhoid vaccine live oral Ty21a: Hypersensitivity to any component of the vaccine or the enteric-coated capsule.

*Typhoid Vi polysaccharide vaccine: Hypersensitivity to any component of the vaccine.

Adverse reactions

In individuals who received 3 doses of typhoid vaccine live oral Ty21a, the most common adverse effects included abdominal pain (6.4%), nausea (5.8%), headache (4.8%), fever (3.3%), diarrhea (2.9%), vomiting (1.5%), and skin rash (1%), with only nausea occurring at a substantially higher rate than placebo.

Within the first 48 hours of vaccination with the typhoid Vi polysaccharide vaccine, the most common local adverse effects experienced in adults were tenderness (98%) and pain (40.7%); the most common systemic adverse effects included malaise (24%) and headache (20.4%). In children, local reactions such as soreness and pain were the most common, and occurred in 13 and 14.3% of children, respectively. Feverishness (a subjective feeling of fever) occurred in 2.9% of children, and was the most common systemic adverse effect.

Precautions

No enhanced messaging available.

ICD codes

CodeTypeDescription
Typhoid vaccination
Z23ICD10CMEncounter for immunization

ICD code information from First Databank (FDB).

Formulary status

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Last reviewed · Source: First Databank (FDB) drug data