The Centers for Disease Control suggests that everyone receive a Hepatitis A vaccine at one year of age. Homosexual males, intravenous drug users and those with chronic liver diseases are advised to receive the vaccine due to greater risks of exposure.
Anyone working alongside animals that are infected with the Hepatitis A virus should also get vaccinated, states the CDC. Travelers to countries with high rates of the virus should receive the vaccine at least two to four weeks before departure, as that is when protection becomes effective. The vaccine is given as two shots spaced six months apart, which increases the length of protection.