Death of a theory

The controversial theory purporting that AIDS spread to people from oral polio vaccine in Africa in the late 1950s has been deflated. The assertion that the vaccine was made from virus-infected chimpanzee kidney cells had been rebutted by three independent laboratories (SN: 9/23/00, p. 203). The research teams have now published their concordant findings–that there’s no chimp DNA in preserved vaccine samples–in the April 26 Nature and the April 27 Science.