Typhoid vaccine

Typhoid vaccine
Vaccine description
Target disease Typhoid
Clinical data
AHFS/Drugs.com Monograph
MedlinePlus a607028
ATC code
Identifiers
ChemSpider
  • none
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Typhoid vaccines are vaccines that prevent typhoid fever.[1] 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).[1] They are about 30 to 70% effective for the first two years depending on the specific vaccine in question.[2] The Vi-rEPA vaccine has been shown to be efficacious in children.[2]

The World Health Organization (WHO) recommends vaccinating all children in areas where the disease is common.[1] Otherwise they recommend vaccinating those at high risk.[1] Vaccination campaigns can also be used to control outbreaks of disease.[1] Depending on the vaccine, additional doses are recommended every 3 to 7 years.[1] In the United States the vaccine is only recommended in those at high risk such as travellers to areas of the world where the disease is common.[3]

The current vaccines are very safe.[1] Minor side effects may occur at the site of injection.[1] The injectable vaccine is safe in HIV/AIDS and the oral vaccine can be used as long as symptoms are not present.[1] While it has not been studied during pregnancy, the non-live vaccines are believed to be safe while the live vaccine is not recommended.[1]

The first typhoid vaccines were developed in 1896 by Almroth Edward Wright, Richard Pfeiffer, and Wilhelm Kolle.[4] Due to side-effects newer formulations are currently recommended.[1] Typhoid vaccines are on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system.[5] The wholesale cost in the developing world is about 4.44 USD per dose as of 2014.[6] In the United States they cost 25 to 50 USD.[7]

Medical uses

Ty21a, the Vi capsular polysaccharide vaccine, and Vi-rEPA are effective in reducing typhoid fever with low rates of adverse effects.[2] Newer vaccines such as Vi-TT (PedaTyph) are awaiting field trials to demonstrate efficacy against natural exposure.[2]

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 2 years.[2] 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 5 years.[8] 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 4 years.[9]

Schedule

Depending on the formulation it can be given starting at the age of two (ViPS), six years old (Ty21a) or 6 months (TCV).[1]

Types

References

  1. 1 2 3 4 5 6 7 8 9 10 11 12 13 World Health Organization (4 April 2018). "Typhoid vaccines: WHO position paper – March 2018" (PDF). Weekly epidemiological record. 93 (13): 153–172.
  2. 1 2 3 4 5 Milligan, R; Paul, M; Richardson, M; Neuberger, A (May 2018). "Vaccines for preventing typhoid fever". The Cochrane Database of Systematic Reviews: CD001261. doi:10.1002/14651858.CD001261.pub4. PMID 29851031.
  3. ↑ "Typhoid VIS". CDC. 2012-05-29. Archived from the original on 8 December 2015. Retrieved 15 December 2015.
  4. ↑ Flower, Darren R. (2008). Bioinformatics for Vaccinology. Chichester: John Wiley & Sons. pp. 40–41. ISBN 9780470699829. Archived from the original on 2015-12-22.
  5. ↑ "WHO Model List of Essential Medicines (19th List)" (PDF). World Health Organization. April 2015. Archived (PDF) from the original on 13 December 2016. Retrieved 8 December 2016.
  6. ↑ "Vaccine, Typhoid". International Drug Price Indicator Guide. Retrieved 6 December 2015.
  7. ↑ Hamilton, Richart (2015). Tarascon Pocket Pharmacopoeia 2015 Deluxe Lab-Coat Edition. Jones & Bartlett Learning. p. 317. ISBN 9781284057560.
  8. ↑ 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.
  9. ↑ 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.
  10. ↑ Helfand, Carley. PaxVax joins the marketed vaccines club with Crucell typhoid buy. FierceVaccines. Archived from the original on 2015-04-02.
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