Typhoid Vaccine

Patient Education

What is typhoid?

Typhoid fever is a serious systemic infection caused by the bacteria called Salmonella typhi.

What is the incidence of Typhoid infection?

The WHO has estimated as of 2019, that 9 million people are infected with Typhoid. Unfortunately, around 110000 people succumb to death due to Typhoid every year. Typhoid fever is seen routinely in most of the underdeveloped and developing countries. In India, annually 4.5 million people suffer from typhoid, with maximum deaths under the age group of 1-4 years followed by 15-54 years.

What is the mode of transmission of Typhoid?

Typhoid is transmitted by the ingestion of food or water contaminated with feces from an infected person. The bacteria grow in the intestine gaining resistance to the immune system and gaining access throughout the body.

What are the symptoms of Typhoid?

Typhoid fever is characterized by a sustained fever as high as 40°C (104°F), profuse sweating, abdominal discomfort, and diarrhea.

What is typhoid vaccine?

Protection against enteric fever might be best achieved by a vaccine that stimulates IgG antibodies to "Vi" capsular polysaccharide in serum, IgG antibodies to "O" antigen in serum, and cell-mediated immune response.

Which are the options available for typhoid vaccines in India?

VI antigen vaccine It contains the VI polysaccharide antigen of S. Typhi. As Vi polysaccharide is the most important virulent factor, the antibodies against Vi antigen are protective against typhoid fever. It is a subunit-inactivated vaccine. It is freely available for use. Vi antigen vaccine is given in the dose of 0.5 ml intramuscularly either on the anterolateral aspect of the thigh or in the deltoid muscle. It is given as a single dose. It is given in children above 2 years of age. Since the VI-antigen vaccine doesn’t induce cell-mediated immunity, the efficacy of the vaccine lasts 2-3 years only. This is why booster doses are recommended every 3 years.

Vi-polysaccharide conjugate typhoid vaccine (TCV) It is a Vi-capsular polysaccharide conjugate typhoid vaccine conjugated with tetanus toxoid. The dose of Vi polysaccharide is 25 µg/0.5 mL. The vaccine has been licensed by the Drug Controller General of India (DCGI) in August 2013 for clinical use in India. The Indian Academy of Pediatrics (IAP) recommends that the TCV can be given between 6-9 months (minimum age 6 months). TCV vaccine can be given up until 45 years of age. As of now, booster doses of TCV are not recommended by the Indian Academy of Pediatrics.

TCV vaccine is preferred over VI antigen vaccine.

Typhibev (Biological E vaccines) is a typhoid conjugate vaccine. It contains the Vi antigen sourced from C. frenundii. Typhibev was licensed for use in India by DCGI in February, 2020. This new vaccine was approved for those infants older than 6 months to adults over 45 years. It is given as a single dose. It is given via intramuscular injection 0.5mg.