Scientists generally agree that HIV-1, which most closely resembles a virus found in chimpanzees, jumped from chimp to human–probably as hunters slaughtered the animals for meat. But Hooper outlines how chimp tissue might have wound up in labs where the experimental polio vaccine was prepared. The theory is based in part on anecdotal recollections that chimp kidneys were sent to Philadelphia’s Wistar Institute, where the vaccine was developed. Lab records are scant or missing, but Dr. Stanley Plotkin, who worked on the vaccine, told NEWSWEEK he believes the chimp scenario is “false.” While monkey tissue is routinely used to grow virus for vaccines, chimp tissue is too rare to be a practical substitute and would never have been considered, he says.
Scientists also debate Hooper’s interpretation of events. He surveys 28 AIDS cases through 1980, and reports that 23 came from what are now the Congo, Rwanda and Burundi–regions where the vaccine was given. And the earliest confirmed blood sample of HIV-1, from the same vicinity, dates to 1959. Dr. Beatrice Hahn of the University of Alabama at Birmingham, however, has traced HIV-1 to a subspecies of chimp living outside the area. And next month other research will propose that the emergence of HIV-1 dates several decades earlier than the polio vaccine.
At least one possible piece of hard evidence exists: a teaspoon-size amount of the original vaccine–now some 40 years old–sits in a stubby little vial with a rubber cork in Wistar’s freezer. It will soon be tested for remnants of the virus and for primate DNA. The tests could be inconclusive. And the debate will continue–against a grim backdrop. AIDS has killed 2.6 million people this year alone, according to figures released last month, and a staggering 22 million inhabitants of sub-Saharan Africa are now HIV-positive. The quest to pinpoint the origin of HIV marches onward. But so too does the horror.
