Hepatitis A vaccine is a vaccine against the hepatitis A virus. The first successful vaccine against it was invented by Maurice Hilleman at Merck. The vaccine protects against the virus in more than 95% of cases and provides protection from the virus for at least fifteen years.There are two types of vaccines: one type contains inactivated hepatitis A virus, the other contains a live but attenuated virus.he vaccine protects against the virus in more than 95% of cases and provides protection from the virus for at least fifteen years. There are two types of vaccines: one type contains inactivated hepatitis A virus, the other contains a live but attenuated virus.