Spread of the virus from pregnant mother to child. Hepatitis B can be spread to the baby in the uterus or during the birth process. This route of transmission is very common in Asia and Africa and explains the very high incidence of hepatitis B in these areas of the world. After a person is exposed to the hepatitis B virus they may not become ill for 1 to 5 months. This period of symptomatic disease may last weeks to months.
Most adults are able to then clear the virus completely from their bodies.
This occurs more often in children and infants. These people can continue to spread the virus to others and often suffer continued inflammation of the liver. Long term carriers of hepatitis B are also at an increased risk of developing cancer of the liver. Some variants of the virus cause warts on the skin. Other variants cause growths in the throat or nose, and other variants cause warty growths on the penis, female genitalia or anus.