Toward a Hepatitis Vaccine

The liver disease known as hepatitis is a stubborn and increasingly common ailment. Infectious hepatitis, usually contracted from contaminated food or water, affected an estimated 100,000 people last year. The more virulent se rum hepatitis, which is transmitted by contaminated blood transfusions and in adequately sterilized hypodermic needles, affected 5,000. At least 1,000 died from the two forms. Unable to identify the guilty virus, doctors could neither prevent the disease nor offer effective treatment. But now, as a result of a complex bit of medical detective work, researchers have isolated what appears to be the hepatitis virus. The development of a vaccine against the disease should be only a matter of time.

The detective work began five years ago, when Australian National University's Dr. Robert Kirk collected blood specimens from a group of aborigines and sent samples to Dr. Baruch S. Blumberg at Philadelphia's Institute for Cancer Research. Blumberg, who was studying the effects of frequent blood transfusions for diseases such as leukemia, tested blood from many parts of the world. Of 24 samples examined, only one from an aborigine caused the test-tube reaction he was looking for. Blumberg found the cause to be an ultramicroscopic viruslike particle. He and Dr. Harvey J. Alter, of the National Institutes of Health (NIH), dubbed the particle "the Australia antigen."

That was in 1965. Now in recent issues of both the A.M.A. Journal and the British journal Lancet, teams from NIH and Columbia University have reported that, contrary to prevailing medical opinion, both infectious and serum hepatitis are probably caused by a single virus. That virus appears to be identical with the Australia antigen.

To prove the point, Dr. Richard J. Hirschman and his colleagues at NIH went back to an old and seemingly cold trail. In 1952-54, a study was made of hemophilia patients who contracted serum hepatitis from injections of an infected blood-clotting factor. The researchers took weekly blood samples but did not find the culprit; so they deep-froze the samples and stored them. In 1968 the 15-year-old samples were thawed out and tested for the Australia antigen. The viruslike particle was found in the blood of 46 (or 74%) of the patients.

Chronic Carriers. One nagging mystery remains: If the Australia antigen is indeed responsible for hepatitis, why is it found in so many apparently unrelated conditions? Hematologists, for example, found it in only one of 1,000 blood samples from healthy Americans, many of whom may have had a mild case of hepatitis without knowing it. The antigen was found in the blood of 30% of mongolism victims living in large institutions, which are often swept by viral epidemics. It is common among leukemia patients who presumably get it through transfusions. It was also discovered in 9% of patients with the "lion face" form of leprosy.*

The most likely answer, according to the researchers, is not that the virus causes such disorders. It is that victims of those diseases are especially susceptible to infection. The hepatitis virus thus finds them an easy target and can even make them chronic carriers.

Whether or not that answer survives further study, several other research groups have seen viruslike particles in blood samples containing the Australia antigen, and work toward the production of a hepatitis vaccine has begun.

* So called because the features swell and distort, giving a leonine appearance.

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