In 1989, 3456 cases of hepatitis B were reported in Canada. It is generally accepted that the true incidence of the disease is about 10 times the reported incidence.
Hepatitis B virus is a major cause of acute and chronic hepatitis, cirrhosis and primary hepatocellular carcinoma. Chronic hepatitis may develop in 10% of infected adults and 90% of infected infants and may progress to cirrhosis and hepatocellular carcinoma. In its acute form hepatitis B is fatal in a small number of cases. The disease is transmitted through sexual contact and infected blood and other body fluids. Carriers frequently show no symptoms until later in life and may therefore infect others unknowingly.
Hepatitis B vaccine has been used in populations that have an established risk of infection with known consequences (e.g., health care workers, male homosexuals and injection drug users).
Recent attention in the Canadian press has focused on the possible association between hepatitis B vaccination and chronic fatigue syndrome (CFS).
You can read the rest of this article here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1488229/pdf/cmaj00290-0039.pdf
Source: [No authors listed] Alleged link between hepatitis B vaccine and chronic fatigue syndrome. CMAJ. 1992 Jan 1;146(1):37-8. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1488229/