Hepatitis B is a vaccine-preventable bloodborne infection. It is a serious viral disease that infects the liver. While the hepatitis B virus (HBV) doesn’t directly damage the liver, it is the body’s immune response to the virus that results in liver injury. Among adults with acute hepatitis B less than 2% fail to clear the virus within six months after infection and develop chronic Hepatitis B infection. To offer a comparison, about 80% of infected newborns and as many as 20% of children under the age of 5 develop persistent infection. Patients with acute hepatitis B must be followed carefully to identify those who have recovered spontaneously and those in whom chronic infection may require specific antiviral drug treatment. Treatment is reserved for those patients in whom viral levels are increased above a specific level and liver enzymes elevations are present. Other patients, for example, so-called inactive carriers with low levels of virus and normal liver enzymes are not currently treated.
In the U.S. the disease is spread predominantly through sex with an infected person, from mother to child during childbirth, (regardless if the delivery is vaginal or through Caesarean section), and through contact with infected blood or body secretions among injection drug users, health care workers, first-responders, and others at risk of exposure. Screening of Asian-Americans for evidence of HBV is recommended because mother to child transmission was common in Asia and other parts of the world prior to the development of immunization programs.
Vaccination provides the safest and most effective protection against hepatitis B for at least 15 years and possibly much longer. Currently, the Centers for Disease Control and Prevention (CDC) recommend that all newborns and individuals up to 18 years of age as well as adults at a high risk of infection (see below) be vaccinated. They also recommend that previously unvaccinated patients with diabetes, age 19 to 59 years, should be vaccinated since such individuals appear to be at increased risk.
Everyone who handles blood or blood products in their daily work should be vaccinated. Three injections over a 6-12 month period are required to provide full protection.
Infants born to infected mothers should receive hepatitis B immune globulin and the hepatitis B vaccine within 12 hours of birth to help prevent infection. Two additional doses of vaccine should be administered at 1 and then at 6-12 months of age. There is increasing evidence that for pregnant women with high levels of HBV, treatment with an oral antiviral at the end of the second or beginning of the third trimester until delivery will reduce the risk that the immunized baby will be infected.
People who develop acute hepatitis B are generally not treated with antiviral drugs because the disease often resolves on its own.
Infected newborns are most likely to progress to chronic hepatitis B, but by young adulthood, most people with acute infection recover spontaneously. Severe acute hepatitis B can be treated with an oral antiviral drug but available data on effectiveness are conflicting and those with acute liver failure are candidates for liver transplantation.
For the treatment of chronic hepatitis B two oral drugs – tenofovir and entecavir – and an injected drug, pegylated interferon are available and considered first-line options. Older drugs, such as lamivudine, telbivudine, and adefovir, are no longer favored. These treatments suppress HBV and improve outcomes. However, treatment is not a cure and small amounts of HBV may persist in the liver for decades.