Hepatitis B vaccine

Hepatitis B virus (HBV) causes a liver infection that can lead to serious complications, including liver cancer. It is common in people throughout the world, particularly in Asia and sub-Saharan Africa. Hepatitis B vaccine (Hep B) almost always prevents this infection.

In response to the vaccine, the body develops antibodies against HBV. This response is known as active immunity.

Hepatitis B vaccine:

• Is usually given as a series of three injections.
• Is safe for women who are pregnant or breast-feeding.
• Provides protection (immunity) against HBV infection for at least 15 years without requiring booster doses or periodic testing.¹
• Cannot cause hepatitis B infection or AIDS.
• May result in pain and discomfort at the injection site or low-grade fever for a short time.

If you are exposed to HBV before you have received all three shots in the vaccination series, a dose of hepatitis B immune globulin (HBIG) usually will prevent infection until the vaccine takes effect.

The U.S. Advisory Committee on Immunization Practices (ACIP) recommends hepatitis B immunization for all children, from birth through 18 years of age.² In addition, adults without immunity who are at high risk for exposure should be vaccinated. Testing for immunity to hepatitis B may be recommended for adults who don't know whether they are immune.

Infant immunizations

Three injections provide long-lasting immunity. All healthy babies who weigh at least 2000g should receive their first dose of hepatitis B vaccine at birth, before leaving the hospital. Babies who are born early (premature) or who weigh less than 2000g should wait until they are 1 month old to get their first dose of hepatitis B vaccine if the mother is not infected with hepatitis B.³

The timing of the remaining 2 doses of the hepatitis B vaccine depends on whether the mother is infected with hepatitis B. Some babies will also need hepatitis B immune globulin (HBIG).

• If it is certain that the mother is not infected with hepatitis B at the time of birth: The second injection of the hepatitis B vaccine should be given at least 1 month after the first. The third injection should be given:
  • At least 4 months after the first injection.
  • At least 2 months after the second injection.
  • At age 6 months or older.
• If the mother is infected with hepatitis B at the time of birth, her baby should get hepatitis B immune globulin (HBIG) within 12 hours of birth (this is in addition to the hepatitis B vaccine at birth). The second injection in the hepatitis B vaccine series is given at 1 to 2 months of age, and the third injection at 6 months.
• If the mother's hepatitis B infection status is not known: The mother will be tested.
  • If she tests positive for hepatitis B, her baby needs to be given hepatitis B immune globulin (HBIG) no later than 1 week after birth. The remaining 2 doses of hepatitis B vaccine should be given as stated above for an infant whose mother is infected with hepatitis B at the time of birth.
  • If she tests negative, her baby will not need hepatitis immune globulin (HBIG). The remaining 2 doses of hepatitis B vaccine should be given as stated above for an infant whose mother is not infected with hepatitis B at the time of birth.

Children and adolescents

The hepatitis B vaccine should be given to anyone 18 years of age or younger who has not previously received it. Adoptees from countries where HBV infection is common should be tested for hepatitis B infection and vaccinated if not immune.

The hepatitis B vaccine is given as a series of three injections in the upper arm or leg.

• The time between the first and second shot should be at least 1 month.
• The time between the second and third shots should be at least 2 months. Ideally, it should be 4 months or more.
• At least 4 months should go by between the first and third shots.

A two-dose series is available for adolescents ages 11 to 15. The time between the first and second shot should be at least 4 months.

Adults at high risk of exposure

Adults who have not received the hepatitis B vaccine series should be immunized when they have an increased risk of exposure. Occupation, travel, health condition, or lifestyle all may increase a person's risk of contracting hepatitis B.

People who live or work where there is risk of exposure include:

• Health care workers and public safety workers who are likely to be exposed to blood or blood products.
• Clients and staff of institutions or residential settings with known or potential HBV carriers.
• People planning extended travel (more than 6 months) to China, Southeast Asia, Africa, and other areas where hepatitis B viral infection is high.

People who have health conditions that put them at high risk for exposure include those who have a severe kidney disease that requires them to have their blood filtered through a machine (dialysis).

People whose lifestyle puts them at high risk for exposure include:

• People who inject illegal drugs.
• Men who have sex with men.
• People who have had more than one sex partner in the past 6 months or who have a history of sexually transmitted diseases.
• Household contacts and sex partners of hepatitis B carriers.
• Prison inmates.

Adult hepatitis B immunization requires three injections. The first and second injections should be given at least 1 month apart. The third injection should be given at least 2 months after the second injection and at least 4 months after the first injection.

If you have already had hepatitis B and have developed protective antibodies to the virus, you do not need the vaccine because you have lifetime protection (immunity) against the infection. If you are not sure whether you have had hepatitis B, you can be tested, or you can be vaccinated without testing. The vaccine is not harmful for you if you are already immune.

If you have chronic HBV infection, the vaccine will be ineffective, although it is not harmful.

If the vaccination series is interrupted and the spacing between doses is longer than recommended, it is not necessary to start the series over or add more doses. The series should be completed from where it was interrupted.

For certain people, such as those with impaired immune systems or who are at high risk of exposure to HBV, health professionals will want to perform a blood test to make sure the vaccine worked (postvaccination testing).

Those who have blood-clotting disorders, such as hemophilia, and have received clotting factors from human donors should be tested for hepatitis B.

Citations

1. World Health Organization (2003). Immunizations, vaccines, and biologicals: Hepatitis B. Available online: http://www.who.int/vaccines/en/hepatitisb.shtml.

2. Centers for Disease Control and Prevention (2007). Recommended immunization schedules for persons aged 0–18 years-United States, 2007. MMWR, 55(51 and 52): Q1–Q4. Also available online: http://www.cdc.gov/mmwr/pdf/wk/mm5551-Immunization.pdf. [Erratum in MMWR, 56(02): 32. Also available online: http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5602a6.htm.]

3. Centers for Disease Control and Prevention (2005). A comprehensive immunization strategy to eliminate transmission of hepatitis B virus infection in the United States, Recommendations of the Advisory Committee on Immunization Practices (ACIP) Part 1: Immunization of infants, children, and adolescents. MMWR, 54(RR-16): 1–23. Also available online: http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5416a1.htm. [Erratum in MMWR, 55(06): 158–159. Also available online: http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5506a6.htm.]