About 1 in every 200 children in the United States will have a moderate to severe disease caused by HiB before the fifth birthday. Serious HiB disease is most common in children between 6 months and 1 year of age. About half of all HiB disease in children happens during the first week of life. This is a viral disease that is transmitted by contact with infected blood or body fluids. Persons with chronic hepatitis B are at increased risk of developing cirrhosis of the liver and liver cancer.
Most infected persons acquire their infection as adolescents or young adults.
Persons who acquire the infection as children and adolescents are more likely to develop chronic hepatitis B than those who acquire it as adults. More than one third of those infected cannot identify how they became infected. Risk behaviors include unprotected sexual activity, body piercing, tattoos and intravenous drug use. Transmission does not occur by the fecal-oral route. This is a very dangerous disease caused by a virus.