Medicine: Encephalitis Vaccine

Around the world, in hot climes and cool, flourishes a group of viruses that attack the central nervous system, causing encephalitis (inflammation of the brain). Many of these viruses—which scientists have classified in two distinct families labeled "A" and "B"—have defied the efforts of virologists and immunologists to devise protective vaccines. Now Johns Hopkins University's Dr. Winston H. Price reports what appears to be a major breakthrough in the war against the encephalitides. The technique depends on family similarity: immunity against two or three members of the B virus family, it appears, gives immunity against the rest of their deadly kin.

In the Proceedings of the National Academy of Sciences, Biochemist Price describes the ''immunological overlap'' among the B viruses, most of which are borne by mosquitoes or ticks. Most feared are Japanese B encephalitis, Russian spring-summer fever, St. Louis encephalitis and Murray Valley fever. *Closely related is dengue ("breakbone fever"), and also yellow fever, against which an effective vaccine has been available since 1937.

Dr. Price's team developed an ingenious technique against B viruses. First they inoculate the human subject with the well-proved yellow-fever vaccine. About four months later they give a shot of live West Nile virus—which infects millions in the Near East, causes distressing fevers but is usually no threat to life. After the yellow-fever shot, the subject throws off the West Nile infection readily—and in the process his system develops antibodies against it. Some months later (Dr. Price is still not sure what is the best interval), he gets a third shot, this one of killed Japanese B virus. The result, studies to date indicate, is across-the-board immunity against all the B viruses.