|Trade names||Typhim Vi, Vivotif|
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Typhoid vaccines are vaccines that prevent typhoid fever. Several types are widely available: typhoid conjugate vaccine (TCV), Ty21a (a live vaccine given by mouth) and Vi capsular polysaccharide vaccine (ViPS) (an injectable subunit vaccine). They are about 30 to 70% effective for the first two years depending on the specific vaccine in question. The Vi-rEPA vaccine has been shown to be efficacious in children.
The World Health Organization (WHO) recommends vaccinating all children in areas where the disease is common. Otherwise they recommend vaccinating those at high risk. Vaccination campaigns can also be used to control outbreaks of disease. Depending on the vaccine, additional doses are recommended every three to seven years. In the United States the vaccine is only recommended in those at high risk such as travelers to areas of the world where the disease is common.
The vaccines available as of 2018 are very safe. Minor side effects may occur at the site of injection. The injectable vaccine is safe in people with HIV/AIDS and the oral vaccine can be used as long as symptoms are not present. While it has not been studied during pregnancy, the non-live vaccines are believed to be safe while the live vaccine is not recommended.
The first typhoid vaccines were developed in 1896 by Almroth Edward Wright, Richard Pfeiffer, and Wilhelm Kolle. Due to side-effects newer formulations are recommended as of 2018. It is on the World Health Organization's List of Essential Medicines.
Ty21a, the Vi capsular polysaccharide vaccine, and Vi-rEPA are effective in reducing typhoid fever with low rates of adverse effects. Newer vaccines such as Vi-TT (PedaTyph) are awaiting[when?] field trials to demonstrate efficacy against natural exposure.
The oral Ty21a vaccine prevents around one-half of typhoid cases in the first three years after vaccination. The injectable Vi polysaccharide vaccine prevented about two-thirds of typhoid cases in the first year and had a cumulative efficacy of 55% by the third year. The efficacy of these vaccines has only been demonstrated in children older than two years. Vi-rEPA vaccine, a new conjugate form of the injectable Vi vaccine, may be more effective and prevents the disease in many children under the age of five years. In a trial in 2-to-5-year-old children in Vietnam, the vaccine had more than 90 percent efficacy in the first year and protection lasted at least four years.
Depending on the formulation it can be given starting at the age of two (ViPS), six (Ty21a), or six months (TCV).
- Vi capsular polysaccharide vaccine: Typhim VI (Sanofi Pasteur); Typherix (GSK)
- Ty21a oral vaccine: Vivotif (PaxVax)
- Typhoid conjugate vaccine: Typbar-TCV (Bharat Biotech)
- Combined hepatitis A and Vi polysaccharide vaccine: ViVaxim and ViATIM (Sanofi Pasteur); Hepatyrix (GSK)
- Activated whole cell vaccine remains available in some parts of the developing world as of 2008[update].
- World Health Organization (2018). "Typhoid vaccines: WHO position paper – March 2018". Weekly Epidemiological Record. 93 (13): 153–172. hdl:10665/272273. Lay summary (PDF).
- World Health Organization (2019). "Typhoid vaccines: WHO position paper, March 2018 - Recommendations". Vaccine. 37 (2): 214–216. doi:10.1016/j.vaccine.2018.04.022. PMID 29661581.
- Milligan, R; Paul, M; Richardson, M; Neuberger, A (May 2018). "Vaccines for preventing typhoid fever". The Cochrane Database of Systematic Reviews. 5: CD001261. doi:10.1002/14651858.CD001261.pub4. PMC 6494485. PMID 29851031.
- "Typhoid VIS". Centers for Disease Control and Prevention (CDC). 29 May 2012. Archived from the original on 8 December 2015. Retrieved 15 December 2015.
- Flower, Darren R. (2008). Bioinformatics for Vaccinology. Chichester: John Wiley & Sons. pp. 40–41. ISBN 9780470699829. Archived from the original on 22 December 2015.
- World Health Organization (2019). World Health Organization model list of essential medicines: 21st list 2019. Geneva: World Health Organization. hdl:10665/325771. WHO/MVP/EMP/IAU/2019.06. License: CC BY-NC-SA 3.0 IGO.
- Lin, FY; Ho, VA; Khiem, HB; Trach, DD; Bay, PV; Thanh, TC; Kossaczka, Z; Bryla, DA; Shiloach, J; Robbins, JB; Schneerson, R; Szu, SC (26 April 2001). "The efficacy of a Salmonella typhi Vi conjugate vaccine in two-to-five-year-old children". The New England Journal of Medicine. 344 (17): 1263–9. doi:10.1056/nejm200104263441701. PMID 11320385.
- Szu, SC (November 2013). "Development of Vi conjugate - a new generation of typhoid vaccine". Expert Review of Vaccines. 12 (11): 1273–86. doi:10.1586/14760584.2013.845529. PMID 24156285. S2CID 23280555.
- "Typhim Vi". U.S. Food and Drug Administration (FDA). 22 July 2017. Retrieved 29 December 2019.
- Helfand, Carley. PaxVax joins the marketed vaccines club with Crucell typhoid buy. FierceVaccines. Archived from the original on 2 April 2015. Retrieved 19 March 2015.
- "Vivotif". U.S. Food and Drug Administration (FDA). 1 February 2018. Retrieved 29 December 2019.
- "Typhoid vaccine prequalified". who.int. 3 January 2018. Retrieved 9 December 2019.