- Ty21a
Ty21a is a vaccine that protects against
typhoid . It is one of two vaccine currently recommended by theWorld Health Organization .cite journal|author=World Health Organization|year=2008|journal=Weekly Epidemiological Record|volume=83|issue=6|pages=49-60|title=Typhoid vaccines: WHO position paper|url=http://www.who.int/wer] The vaccine offers between 33 and 78% protection. The vaccine is most commonly used to protect travellers to endemic countries, but there is no reason why the vaccine could not be used in large scale public prevention programmes.The vaccine is given by mouth. The vaccine is presented either as capsules or a liquid suspension. The vaccine must be stored at 2 to 8 °C, but will retain its potency for 14 days at 25°C.
Dosing
The recommended dose varies according to country.
In the US and Canada, an initial course of 4 doses on alternate days is recommended. Full protection is achieved 7 days after the last dose. In the US, a booster dose is recommended after 5 years. In Canada, a booster dose is recommended after 7 years.
In Australia and Europe, and initial course of 3 doses on alternate days is recommended. Protection is achieved 7 days after the last dose. A booster is recommended every 3 years for people living in endemic areas, but every year for people travelling from non-endemic to endemic areas.
References
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