Where was the first vaccine against hepatitis A developed?

The first hepatitis A vaccines were developed in the United States and licensed in the 1990s. Hepatitis A spreads mainly through contaminated food, water, or close contact, so vaccination became important in outbreak prevention. The vaccine is made from inactivated virus and provides long-lasting protection. It has been adopted widely in countries that chose to add it to routine immunization programs. Public-health campaigns also use it during outbreaks and for travelers to risk areas.