Hepatitis B vaccine: onward and upward.

There already is a blood-derived vaccine against hepatitis B, but that doesn't mean there isn't room for improvement. An experimental, yeast-engineered recombinant DNA vaccine has recently proven successful in adults and infants (SN: 7/27/85, p. 55), and now researchers are reporting good results with a recombinant vaccine manufactured by a mammalian cell line. An estimated 800,000 or more people in the United States and 200 million people worldwide are carriers of the hepatitis B virus, which can cause chronic liver disease and liver cancer.

The currently marketed vaccine is produced from the blood of infected people. While the safety of the product has been proven, the source -- hepatitis B carriers -- could eventually disappear. "If vaccine prevention works," says MArtin rosenberg of Smith Kline & French Laboratories in Philadelphia, who chaired a session on recombinant vaccines at the meeting, "there will be no future source of the vaccine."

John M. Zahradnik and his colleagues at Baylor College of Medicine in Houston and Georgetown University in Washington, D.C., vaccinated 200 healthy men with a mammalian recombinant vaccine and 20 men with the currently marketed vaccine. within four weeks, 70 percent of recombinant vaccinations "took," compared with only 25 percent in the other group; eventually 95 percent of the men in both groups were protected.

"Our vaccine seems to be more immunogenic [than the current vaccine] and that may be important in the long run," says Zahradnik. Another advantage: The U.S. Department of Health and Human Services projects that the price of the recombinant vaccine will be less than that of the one now in use.