HBsAg-positive Swedish blood donors: natural history and origin of infection

99 HBsAg-positive blood donors (BDs) were discovered in G?teborg during 1970-84. Of the 82 patients where the outcome is known 46 had transient and 36 persistent antigenemia. Chronic hepatitis was found in 6 patients while 30 were asymptomatic carriers. Three BDs had died, 1 of them from cholangiocellular cancer. An obvious mode of transmission was demonstrated for 19 BDs, i.v. drug abuse being the most frequent one. Five BDs originated from countries with a known high prevalence of hepatitis B virus (HBV). Family contacts of the remaining carriers had serological markers for HBV in the following frequencies: mothers 46%, siblings 39%, fathers 25%, children 13%, spouses 10%. Only children of female carriers had markers for HBV infection. Intrafamiliar transmission during childhood is an important route of transmission even in a country with low HBV endemicity and amongst people without connection with endemic regions. This population may be susceptible to the consequences of a long-term carriership of HBV.