Hepatitis B: Epidemiology and prevention in developing countries.

Hepatitis B virus (HBV) infection is a serious global public health problem. The infection may be transmitted through sexual intercourse, parenteral contact or from an infected mother to the baby at birth and, if contracted early in life, may lead to chronic liver disease, including cirrhosis and hepatocellular carcinoma. On the basis of the HBV carrier rate, the world can be divided in 3 regions of high, medium and low endemicity. The major concern is about high endemicity countries, where the most common route of infection remains vertical transmission from mother to child. Screening of all pregnant women and passive immunization with human hepatitis B immunoglobulin are not affordable for many developing countries. The infection rate can be reduced by modifying behavior, improving individual education, testing all blood donations, assuring asepsis in clinical practice and screening all pregnant women. However, availability of a safe and efficacious vaccine and adoption of appropriate immunization strategies are the most effective means to prevent HBV infection and its consequences. The unsolved problem for poorest countries, where the number of people currently infected is high, is the cost of the vaccine. A future challenge is to overcome the social and economic hurdles of maintaining and improving a prevention policy worldwide to reduce the global burden of the disease.