Hepatitis B virus infection in Singapore.
Although Singapore is in an endemic region for hepatitis B infection, the hepatitis B carriage rate of 5-6% is relatively low. The highest positivity rates for hepatitis B surface antigen (HBsAg) are found in the paediatric age group, with another peak in 40-49 year olds. Studies suggest that, although perinatal transmission is an important route of infection, most children acquire the virus through horizontal transmission between family members. Viral replication continues at a high rate in young carriers and tends to slow down with increasing age. Up to 50% of hepatitis B carriers in Singapore have chronic hepatitis, shown by raised serum ALT values and liver histology, and about 10% are infected with the precore mutant virus. About 20% of carriers have cirrhosis. Among patients with HCC, up to 75% are HBsAg positive, of whom 45% are still viraemic. Mass vaccination against hepatitis B was introduced into Singapore on a voluntary basis in 1983, with compulsory vaccination of babies born to HBeAg positive mothers since 1985. The number of cases of acute hepatitis B has fallen by 60% between 1989 and 1995 although the problems of the longterm complications of chronic hepatitis B still need to be tackled.
Guan
R
R
Mount Elizabeth Medical Centre and National University Hospital, Singapore.
D000367:Age Factors; D006528:Carcinoma, Hepatocellular / Q000821:virology; D006509:Hepatitis B / Q000150:complications / Q000453:epidemiology* / Q000517:prevention & control / Q000628:therapy; D017325:Hepatitis B Vaccines; D006801:Humans; D008113:Liver Neoplasms / Q000821:virology; D012846:Singapore / Q000453:epidemiology
D017325:Hepatitis B Vaccines