Hepatitis_A_vaccine
Hepatitis A vaccine
Vaccine to prevent hepatitis A
Hepatitis A vaccine is a vaccine that prevents hepatitis A.[1][2] It is effective in around 95% of cases and lasts for at least twenty years and possibly a person's entire life.[3] If given, two doses are recommended beginning after the age of one.[1] It is given by injection into a muscle.[1] The first hepatitis A vaccine was approved in Europe in 1991, and the United States in 1995.[4] It is on the World Health Organization's List of Essential Medicines.[5][6]
The World Health Organization (WHO) recommends universal vaccination in areas where the disease is moderately common.[1] Where the disease is very common, widespread vaccination is not recommended as all people typically develop immunity through infection during childhood.[1] The US Centers for Disease Control and Prevention (CDC) recommends vaccinating:[7]
- All children aged 12–23 months
- Unvaccinated children and adolescents aged 2–18 years
- International travelers
- Men who have sex with men
- People who use injection or non-injection drugs
- People who have occupational risk for infection
- People who anticipate close contact with an international adoptee
- People experiencing homelessness
- People with HIV
- People with chronic liver disease
- Any person wishing to obtain immunity[8]
In addition, a person who has not previously received hepatitis A vaccine and who has direct contact with someone with hepatitis A should get hepatitis A vaccine within two weeks after exposure.[8]
Severe side effects are very rare.[1] Pain at the site of injection occurs in about 15% of children and half of adults.[1] Most hepatitis A vaccines contain inactivated virus while a few contain weakened virus.[1] The ones with weakened virus are not recommended during pregnancy or in those with poor immune function.[1] A few formulations combine hepatitis A with either hepatitis B or typhoid vaccine.[1]
Soreness or redness where the shot is given, fever, headache, tiredness, or loss of appetite can happen after hepatitis A vaccine. As with any medicine, there is a very remote chance of a vaccine causing a severe allergic reaction, other serious injury, or death.[8]