There are two inactivated hepatitis A vaccines available in the United States. Both are available for anyone twelve months of age or older, although adults (over age eighteen) receive a higher dose. The vaccines are recommended for children between one and two years of age, with a booster six months later. In addition, the vaccine is recommended for anyone at risk of contracting hepatitis A, such as an international traveler or someone with preexisting liver disease. Again, there is a recommended booster dose six months later.
There is also an immune globulin that protects against hepatitis A. An immune globulin is a mixture of antibodies that protects against certain diseases, in this case hepatitis A. An immune globulin is useful if you have to protect a child less than twelve months old or if you don’t have the two or three weeks of time needed to wait for a vaccine to become effective.
An example of the latter situation would be daycare workers who find that one of the children in their class has just been diagnosed with hepatitis A. Because the virus spreads even before the child becomes ill, the workers have probably already been exposed. If they receive the immune globulin immediately, they have an 85 percent chance of being protected from developing the illness from this exposure. The workers should also receive the vaccine because the benefits of the immune globulin wear off after three to six months.