Hepatitis B: Hepatitis B vaccine

How can we prevent hepatitis B?

Hepatitis B is a preventable disease. Vaccination and post-exposure prophylaxis have significantly reduced rates of infection. Risk can also be reduced by avoiding unprotected sex, contaminated needles, and other sources of infection.

How effective is vaccination for hepatitis B?

The hepatitis B vaccine contains a protein (antigen) that stimulates the body to make protective antibodies. Examples of hepatitis B vaccines available in the United States include hepatitis b vaccine-injection (Engerix-B, Recombivax-HB). Three doses (given at 0, 1, and 6 months) are necessary to assure protection. There are also combination vaccines on the market that provide protection against hepatitis B and other diseases.

Examples are:

  • Hepatitis-b-hepatitis-a vaccine – injection (Twinrix), which provides protection against both hepatitis A and hepatitis B.
  • Haemophilus B/hepatitis B vaccine injection (Comvax) provides protection against hepatitis B and Haemophilus influenzae type b (which causes meningitis).
  • Pediarix provides protection against hepatitis B, tetanus, pertussis (whooping cough), and polio.
    Hepatitis B vaccines are efficient and safe. About95% of vaccinated individuals forms effective antibodies when they get the vaccine and are protected from hepatitis B. In healthcare workers, high-risk public safety workers, dialysis patients, and sexual partners of infected persons, a blood test for antibodies is recommended after vaccination to ensure that the antibodies have been formed. If antibodies are not formed, revaccination may improve response, especially in infants. However, a small proportion of individuals will never respond to hepatitis B vaccination. Side effects from the vaccine are usually mild and include soreness at the site of injection. The risk of serious allergic reactions (anaphylaxis) is less than one per million doses. Vaccination has reduced the number of new cases of hepatitis B by more than 75% in the United States.

In the United States, hepatitis B vaccination is recommended for all infants at birth. Older children and adolescents should receive the vaccine if they are not vaccinated at birth.

Adults in high risk situations also are advised to receive hepatitis B vaccine. This includes:

  • Health care workers
  • Dentists
  • Intimate and household contacts of patients with chronic hepatitis B infection
  • Public safety workers who may be exposed to blood
  • Men who have sex with men(homosexuals)
  • Individuals with multiple sexual partners
  • Dialysis patients
  • Injection drug users
  • Persons with chronic liver disease
  • Residents and staff in institutions that care for persons with developmental disabilities
  • Persons infected with HIV
  • Persons who require repeated transfusions or blood products.

Centers that serve high-risk individuals are encouraged to provide the vaccine to their clients. Such centers include dialysis units, drug treatment facilities, sexually transmitted diseases clinics and correctional facilities. Some countries have a high prevalence of hepatitis B in their population. Travelers who visit these countries for a prolonged period of time (usually six months) and those who may be exposed to blood or semen should be vaccinated.

How effective is hepatitis B immune globulin (HBIG) in preventing hepatitis B?

HBIG is a product that contains antibodies against hepatitis B. When injected, it provides temporary protection against hepatitis B. HBIG is used when people have had significant exposure to the virus. An example would be an accidental needle stick in an unvaccinated health care worker from a needle contaminated with blood from a person with hepatitis B. HBIG should be given as soon as possible after exposure, preferably within seven days. Persons who need HBIG should also receive hepatitis B vaccine. HBIG also is given to patients with hepatitis B following liver transplantation to suppress the hepatitis B virus in the transplanted liver.

What is post-exposure immunoprophylaxis for hepatitis B virus?

Unvaccinated individuals who are exposed to a known case of hepatitis B or to a person at high risk for hepatitis B should be evaluated by a physician. Examples of such exposures are needle stick injuries in health care workers or sexual intercourse with an infected person. If the exposure is significant, the physician will recommend vaccination and also may recommend an injection of hepatitis B immune globulin (HBIG). HBIG is prepared from the plasma of blood donors and contains antibodies to hepatitis B. Vaccination and HBIG can substantially reduce the risk of disease in persons exposed to hepatitis B if given within one week of a needle stick or two weeks of sexual intercourse.

Vaccination provides long-term immunity in people who respond to the vaccine. There is no need for HBIG if an exposure occurs to a vaccinated person who is known to respond to the vaccine; however, a blood test might be drawn to verify that the person did respond to the vaccine.

How is transmission of hepatitis B virus from mother to newborn infant prevented?

Infected mothers can pass hepatitis B to their newborn infants. All pregnant women should have blood tested to determine if they are infected with hepatitis B. Infants born to infected mothers should receive HBIG and hepatitis B vaccine at birth. This is 85% to 95% effective in eliminating the risk of hepatitis B in the infant.

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