Humans Can Acquire Immunity to Hepatitis C

A study has found that humans can acquire immunity to the hepatitis C virus (HCV), suggesting that vaccines could be used to protect those with the virus from long-term complications. Conducted by researchers at Johns Hopkins Medical School (Baltimore, MD, USA), the study was published in the April 26, 2002, issue of The Lancet.

The researchers compared the incidence and persistence of HCV in 164 people whose blood tests revealed no evidence of prior HCV infection and 98 people who had been infected in the past but were not infected at the time of the study. Previously infected people were almost half as likely to develop new infections as those never infected (12% vs 21%). Among HIV-1 negative people, those previously infected were 12 times less likely to develop infection than those infected for the first time. The results mirrored those of chimpanzee studies, which found that animals previously infected or vaccinated could be re-infected but their infections were less likely to persist, compared to animals infected for the first time.

"Our findings indicate that vaccines should be developed to reduce the burden of liver disease associated with hepatitis C infection,” said David. L. Thomas, associate professor of medicine at Hopkins and lead author of the study. About 170 million people worldwide have been infected with HCV, and about 85% of them develop persistent infection and are at risk of serious complications such as liver cirrhosis and liver cancer, according to Dr. Thomas. Recent vaccine research in primates is showing promise.




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