My son is now 13 years old. On May 3, 1999, he received his first hepatitis B inoculation. He received the second on June 3, and the third on July 2. I was notified today that the third shot was given too early, and that he needs to have another one given now. I am concerned about him receiving a fourth hepatitis B shot, and the possible adverse effects overall. Please advise.

B.

Hepatitis B is one of the most common causes of liver disease in the world. It can cause both severe acute hepatitis (liver infection) as well as chronic disease leading to cirrhosis and liver cancer. Vaccination provides protection against infection in over 90 percent of people. Currently, public health officials recommend that every infant born in the United States receive the vaccine.

The vaccine is very safe. There are no live viral components in it, so there is no possible way to develop hepatitis B from the vaccine. As you found out, there are standard dosing regimens that must be followed to achieve optimal effectiveness. An important factor in the vaccination regimen is that the third dose should be given at least two months after the second dose. In fact, it can be given many months after and immunization will still be effective.

You are concerned about your son receiving a fourth dose of the vaccine. This should be nothing to worry about. There has been some concern about the safety of the vaccine, linking it in some reports to sudden infant death syndrome (SIDS), multiple sclerosis and other problems. Fortunately, most if not all of these reports have been unfounded. As the U.S. Centers for Disease Control explain, any time you give a vaccine to millions of people each year, there have to be some unfortunate coincidences. For example, if 5,000 infants die of SIDS each year, and all infants receive the vaccine, then some would die of SIDS soon after getting the vaccine -- this would have to occur sometimes by coincidence alone. It certainly does not mean that the vaccine caused SIDS. This same concept probably holds true with multiple sclerosis and other illnesses.

Your son should have no problem receiving another dose. In fact, when someone does not fully respond to three doses of the vaccine, we give another dose or two to stimulate immunity.