US air force recruits in the 1950s were already displaying rates of hepatitis C infection similar to current US prevalence amongst blood donors, and only 11% have died of liver disease 45 years later, according to a team of US researchers, who say that their findings suggest that "healthy HCV-positive persons may be at less risk for progressive liver disease than is currently thought".
The team tested frozen blood samples from 8,568 air force recruits who underwent medical exams between 1948 and 1954. They found 0.2% had antibodies to hepatitis C, with a higher rate among African-Americans (1.8%). Over the subsequent 45 years, HCV-positive individuals had a 3.5 times greater risk of dying of liver disease.
Previous studies have not been able to follow HCV-positive individuals beyond 25 years, so the lifetime risk of HCV infection was previously unknown, and this is the first study which looks at the prognosis of individuals infected whilst young.
The researchers were able to determine that the genotype of HCV in all but one infected case was 1b. HCV 1b has been described as more aggressive (and less responsive to treatment) than other genotypes, yet the average age at death of the HCV-infected recruits was not significantly different from that of uninfected individuals.
Studies in Japan, Spain and Italy have suggested much higher rates of liver disease in HCV-positive individuals, particularly of hepatocellular carcinoma, and the authors of the newly published US study suggest that other co-factors need to be examined more rigorously to determine how much of a bearing age at infection, viral genotype, alcohol consumption and sex have on long-term prognosis.
Reference
Seeff LB et al. 45 year follow-up of hepatitis C virus infection in healthy young adults. Annals of Internal Medicine 132: 105-111, 2000.