User:Mr. Ibrahem/Hepatitis A vaccine

Hepatitis A vaccine is a vaccine that prevents hepatitis A, a disease of the liver. It used in children and adults, is well-tolerated, safe and effective. Around 95% or more of those vaccinated get protection 2-to-4 weeks following the first dose. A second dose given 6 to 12 months later provides long-term protection; possibly for a person's entire life. It is given by injection into a muscle, but some brands can be injection just under skin if the person has haemophilia or is taking blood-thinning medicines.

The World Health Organization (WHO) recommends universal vaccination in areas where the disease is moderately common. Where the disease is very common, widespread vaccination is not recommended as all people typically develop immunity through infection during childhood. As of 2018, routine hepatitis A vaccination in not part of any African country's Expanded Program on Immunization. In the US, it is recommended in adults who are at high risk and all children over age one-year. One dose of the vaccine, is also advised, for infants age 6-11 months who are travelling to a high risk area; but should receive the 2-dose course as usual after age one. High risk groups include: certain occupations, close contacts with people with acute hepatitis A, men who have sex with men, people who use illicit drugs, people with chronic liver disease or blood clotting conditions, the homeless, and 2 to 4 weeks before travelling to areas were the disease is common.

No severe side effects are linked to the vaccine. Mild self-limiting pain and swelling at the site of injection occurs in about one-in-five children and half of adults. Less than 5% of people receiving the vaccine may have a moderate side effect such as tiredness, low fever, diarrhoea, vomiting, and headache. Most hepatitis A vaccines contain inactivated virus while a few contain weakened virus. The ones with weakened virus are not recommended during pregnancy or in those with poor immune function. A few formulations combine hepatitis A with either hepatitis B or typhoid vaccine.

The first hepatitis A vaccine was licensed in 1992. The first dose, globally, was administered in 1992. It is on the World Health Organization's List of Essential Medicines. In the United States it costs US$50–100. In the UK, one dose of hepatitis A vaccine costs the NHS just over £20. As of 2021, millions of doses have been given worldwide.