How is viral hepatitis prevented?

Prevention of hepatitis involves measures to avoid exposure to the viruses, using immunoglobulin in the event of exposure, and vaccines. Administration of immunoglobulin is called passive protection because antibodies from patients who have had viral hepatitis are given to the patient. Vaccination is called active protection because killed viruses or noninfective components of viruses are given to stimulate the body to produce its own antibodies.

Avoidance if exposure to viruses

Prevention of viral hepatitis, like any other illness, is preferable to reliance upon treatment. Taking precautions to prevent exposure to another individual's blood (exposure to dirty needles), semen (unprotected sex), and other bodily waste (stool) will help prevent the spread of these viruses.

Use of immunoglobulins

Immune serum globulin (ISG) is human serum that contains antibodies to hepatitis A. ISG can be administered to prevent infection in individuals who have been exposed to hepatitis A. ISG works immediately upon administration, and the duration of protection is several months. ISG usually is given to travelers to regions of the world where there are high rates of hepatitis A infection and to close or household contacts of patients with hepatitis A. ISG is safe with few side effects.

Hepatitis B immune globulin or HBIG (BayHep B), is human serum that contains antibodies to hepatitis B. HBIG is made from plasma (a blood product) that is known to contain a high concentration of antibodies to the hepatitis B surface antigen. If given within 10 days of exposure to the virus, HBIG almost always is successful in preventing infection. Even if given a bit later, however, HBIG may lessen the severity of HBV infection. The protection against hepatitis B lasts for about three weeks after the HBIG is given. HBIG also is given at birth to infants born to mothers known to have hepatitis B infection. In addition, HBIG is given to individuals exposed to HBV because of sexual contact or to healthcare workers accidentally stuck by a needle known to be contaminated with blood from an infected person.

Vaccination

Hepatitis A. Two hepatitis A vaccines are available in the US, Havrix and Vaqta. Both contain inactive (killed) hepatitis A virus. For adults, two doses of the vaccine are recommended. After the first dose, protective antibodies develop in 70% of vaccine recipients in 2 weeks and more than 95% of recipients in 4 weeks. After two doses of the hepatitis A vaccine, immunity against hepatitis A infection is believed to last for many years.

Individuals at increased risk for acquiring hepatitis A and individuals with chronic liver disease (e.g., cirrhosis or chronic hepatitis C) should be vaccinated. Although individuals with chronic liver disease are not at increased risk for acquiring hepatitis A, they can develop serious (sometimes fatal) liver failure if infected with hepatitis A and, thus, they should be vaccinated.

Individuals at increased risk of acquiring hepatitis A are:

• Travelers to countries where hepatitis A is common
• Men who have sex with men
• Illegal drug users (either injection or non-injection drug use)
• Researchers working with hepatitis A or primates that are susceptible to infection with hepatitis A
• Patients with clotting factor disorders who are receiving clotting factor concentrates that can transmit hepatitis A

Some local health authorities or private companies may require hepatitis A vaccination for food handlers.

Because protective antibodies take weeks to develop, travelers to countries where hepatitis A is common should be vaccinated at least 4 weeks before departure. The Centers for Disease Control (CDC) recommends immunoglobulin be given in addition to vaccination if departure is prior to 4 weeks. Immunoglobulin provides quicker protection than the vaccines, but the protection is short-lived.

Hepatitis B

For active vaccination, a harmless hepatitis B antigen is given to stimulate the body's immune system to produce protective antibodies against the surface antigen of hepatitis B. Vaccines that are currently available in the United States are made (synthesized) using recombinant DNA technology (joining DNA segments). These recombinant hepatitis B vaccines (Energix-B and Recombivax-HB) are constructed to contain only that part of the surface antigen that is very potent in stimulating the immune system to produce antibodies. The vaccine contains no viral component other than the surface antigen and is not infectious. Hepatitis B vaccines should be given in three doses with the second dose 1-2 months after the first dose, and the third dose 4-6 months after the first dose. For the best results, the vaccinations should be given in the deltoid (shoulder) muscles and not in the buttocks.

Hepatitis B vaccines are 95% effective. Five percent of vaccinated individuals will fail to develop the necessary antibodies for immunity after the three doses. Patients with weakened immunity (such as HIV infection), elderly patients, and patients undergoing kidney hemodialysis are more likely to fail to respond to the vaccines.

Hepatitis B vaccine is recommended for:

• All infants
• Adolescents under 18 years of age who did not receive hepatitis B vaccine as infants
• People occupationally exposed to blood or body fluids
• Residents and staff of institutions for the developmentally disabled
• Patients receiving kidney hemodialysis
• Hemophiliacs and other patients receiving clotting factor concentrates
• Household contacts and sexual partners of patients infected with hepatitis B chronically
• Travelers who will spend more than 6 months in regions with high rates of hepatitis B infection
• Injection drug users and their sexual partners
• Men who have sex with men, men or women with multiple sex partners, or recent infection with a sexually transmitted infection
• Inmates of long-term correctional facilities
• All pregnant women should have a blood test for the antibody to hepatitis B surface antigen. Women who test positive for hepatitis B risk transmitting the virus to their infants during labor, and, therefore, infants born to mothers with hepatitis B infection should receive HBIG in addition to hepatitis B vaccine at birth. The reason for giving both immunoglobulin and vaccine is that even though hepatitis B vaccine can offer long lasting, active immunity, immunity takes weeks or months to develop. Until active immunity develops, the short-lived, passive antibodies from the HBIG protect the infant.

Unvaccinated individuals exposed to materials infected with hepatitis B (such as healthcare workers stuck by a contaminated needle) will need HBIG in addition to hepatitis B vaccine for the same reason as infants born to mothers with hepatitis B infection.

Hepatitis C

There is currently no vaccine for hepatitis C.

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