Hepatitis B immunization for adults

General information
Hepatitis B is a viral infection of the liver that sometimes becomes chronic. Eventually, it may lead to liver failure or liver cancer. Hepatitis B spreads through exposure to fresh or dried infected blood or body fluids (such as semen, saliva and vaginal fluids). Often, the infected person has no symptoms and is unaware he or she is carrying the virus. People who are involved in activities or occupations that include exposure to blood or body fluids have a high risk for developing hepatitis B. However, some people who develop the disease have no identified risk factors. Hepatitis B can also spread from an infected mother to her baby, most commonly during birth.
The hepatitis B vaccine (HBV, Engerix-B, Recombivax HB) is made from an inactivated form of the hepatitis B virus.


Recommendations
The hepatitis B vaccine is recommended for people at high risk for contracting hepatitis B, including homosexual and bisexual men and people who:
have multiple sexual partners
have a sexually transmitted disease (STD)
inject illegal drugs
are long-term male prison inmates
live or work in an institutional setting
are routinely exposed to blood, blood products or human bites (such as health care workers, members of the police force, firefighters and military personnel)
live or work in an institution for the developmentally disabled
live in, travel to or emigrated from a country where hepatitis B is prevalent (including infants and children of immigrants from areas where hepatitis B is prevalent)
are household or sexual contact with someone who is infected with hepatitis B
are family members of adoptees who are infected with hepatitis B
receive clotting factors for a blood clotting disorder
receive hemodialysis (an external method of removing unwanted material from the blood, which is normally a function of the kidneys)
unvaccinated adolescents

Dose
The hepatitis B vaccine is given in three injections, with the second dose often given one to two months after the first, and the third given four to six months after the first. (Your doctor may recommend a slightly different schedule.) If the interval between doses is longer than recommended, you will not have to start the series over or receive extra doses. If the interval between doses is less than recommended, then that dose should not be counted as part of series.
For people over age 18, a combined hepatitis A and hepatitis B vaccine is available. You'll need three doses, following the hepatitis B vaccine schedule.


Effectiveness/booster
After three injections, the vaccine provides 80 to 100 percent protection from hepatitis B. Length of protection is uncertain, but appears to be more than 15 years. A booster is not recommended at this time for healthy adults.

Side effects
Side effects from the vaccine are usually minor and include soreness, redness, warmth or swelling at the injection site; low-grade fever; fatigue; headache; and irritability. Side effects typically begin within 24 hours and usually disappear within 48 to 72 hours. Allergic reactions are possible, but rare.

Who should wait to receive the vaccine
The vaccine may be postponed if you have a moderate to severe acute illness.

Who should not receive the vaccine
You should not receive the vaccine if you've had a serious reaction or allergy to a prior hepatitis B vaccination or baker's yeast.

Pregnancy-specific information
Hepatitis B screening is performed during pregnancy. If you're positive, your baby will need postexposure prophylaxis at birth. If you're negative, vaccination during pregnancy can be done, preferably as soon as possible.