Hepatitis B Important Facts Hepatitis B is a viral infection that damages the liver and can cause acute or chronic disease. The virus is spread through the blood or other body fluids of an infected person. Approximately 780,000 people die from hepatitis B each year. Hepatitis B is a major occupational hazard affecting health workers. Hepatitis B can be prevented with the safe and effective vaccines available. Hepatitis B is a potentially life-threatening infection of the liver caused by the hepatitis B virus. It is a serious global health problem. It can cause chronic liver disease and chronic infection, and patients are at high risk of dying from cirrhosis and liver cancer. More than 240 million people suffer from chronic (long-term) liver infection disease, and about 780,000 people die each year from acute or chronic hepatitis B. The 2006 epidemiological survey of hepatitis B in China showed that the HBsAg carriage rate in our general population aged 1-59 years was 7 .18%, and only 0.96% in children under 5 years old. According to this projection, there are about 93 million people with chronic HBV infection in China, including about 20 million cases of chronic hepatitis B patients. Since 1982, a hepatitis B vaccine has been available. The hepatitis B vaccine is 95% effective in preventing infection and its chronic consequences, and was the first vaccine to prevent a major human cancer. Transmission In high endemicity areas, the most common route of transmission of hepatitis B virus is from mother to child or between children in early childhood. In low endemic areas, sexual transmission and use of contaminated needles (especially among intravenous drug addicts) are the main routes of infection, but perinatal transmission or child-to-child transmission in early childhood can account for more than one-third of chronic infections. Hepatitis B virus can survive outside the body for at least 7 days. During this time, the virus can still cause infection if it enters the body of a person who has not received the hepatitis B vaccine. Hepatitis B virus is not transmitted through the respiratory and digestive tracts, so daily school, work or household contacts, such as working in the same office (including sharing office supplies such as computers), shaking hands, hugging, sharing toilets, etc. without blood exposure, are generally not associated with hepatitis B virus transmission. Epidemiological and experimental studies have also not found that hepatitis B virus can be transmitted by blood-sucking insects (mosquitoes, bedbugs, etc.). The infectivity of hepatitis B patients and carriers depends mainly on the level of HBV DNA in the blood, but not on the serum ALT, AST or bilirubin levels. The incubation period of hepatitis B virus averages 75 days, but may vary from 30 to 180 days. Hepatitis B virus can be detected 30 to 60 days after infection, with varying durations. Symptoms Most people do not have any symptoms during the acute or chronic infectious period. However, some people have acute illness with symptoms that can last for several weeks, including yellowing of the skin and eyes (jaundice), dark urine, extreme fatigue, nausea, vomiting and abdominal pain. The hepatitis B virus may cause chronic liver infection in some people, which may later develop into cirrhosis or liver cancer. More than 90 percent of healthy adults infected with the hepatitis B virus will be cured and completely clear of the virus within six months. Who is at risk for chronic disease? The likelihood of a hepatitis B virus infection becoming a chronic disease depends on a person’s age at the time of infection. Children under 6 years of age infected with hepatitis B virus are most likely to become chronically infected: about 80%-90% of infants infected with the virus in the first year of life become chronically infected; 30%-50% of children infected before age 6 become chronically infected. Adults: Less than 5% of healthy adults infected with hepatitis B virus become chronically infected; 15-25% of adults chronically infected in childhood will die from hepatitis B-induced liver cancer or cirrhosis. Diagnosis Clinically, it is not possible to distinguish hepatitis B from hepatitis caused by other viral agents. Therefore, the diagnosis must be confirmed by laboratory tests. Several blood tests are available to diagnose and monitor patients with hepatitis B. This can be used to differentiate between acute and chronic infections. Laboratory diagnosis of hepatitis B infection is primarily made by testing for hepatitis B surface antigen (HBsAg). Chronic infection is characterized by the persistence (>6 months) of hepatitis B surface antigen positivity (with or without hepatitis B e antigen). The persistence of hepatitis B surface antigen positivity is a major risk marker for the development of chronic liver disease and the progression to hepatocellular carcinoma later in life. Treatment There is no specific treatment for acute hepatitis B. The goal of treatment is to maximize long-term suppression of the hepatitis B virus, reduce inflammatory necrosis and liver fibrosis, delay and reduce the occurrence of liver failure, cirrhosis, hepatocellular carcinoma and their complications, and thereby improve quality of life and prolong survival. Patients with chronic hepatitis B can be treated with antiviral drugs, including telbivudine and entecavir, and interferon. Treatment can slow the progression of cirrhosis, reduce the incidence of hepatocellular carcinoma, and improve long-term survival. Liver cancer is almost always fatal and often occurs when people are most productive and have family responsibilities. Most patients with liver cancer die within a few months of diagnosis. With surgery and local ablation, interventional and non-surgical treatments, patients can live several years longer. Prevention Vaccination against hepatitis B is the primary method of preventing hepatitis B. Three doses of hepatitis B vaccine are required for the entire course, following a 0, 1, and 6 month schedule in which the first dose is followed by the second and third doses at 1 and 6 month intervals. Hepatitis B vaccination for newborns is required within 24 hours after birth, the earlier the better. More than 95% of infants, children and adults who receive the full course of vaccine will have a protective level of antibodies. Protection lasts for at least 20 years and lifelong immunity is possible. All unvaccinated children and adolescents under 18 years of age should be vaccinated. An increasing number of people in high-risk groups are likely to become infected, so they should also be vaccinated. These include: people who require frequent use of blood or blood products, dialysis patients, solid organ transplant recipients, and medical personnel; people who work in child care facilities, are immunocompromised, and are vulnerable to trauma; family members and sexual contacts of people with chronic hepatitis B virus infection; people who have multiple sexual partners, as well as men who have sex with men, and people who inject drugs intravenously; and travelers who have not completed the full course of hepatitis B vaccination should be vaccinated before traveling to hepatitis B Hepatitis B vaccine should be administered prior to travel to endemic areas.