Did the end of smallpox vaccination cause the explosive spread of HIV?
Vaccinia immunisation, as given to prevent the spread of smallpox, produces a five-fold reduction in HIV replication in the laboratory. Researchers writing in the open access journal BMC Immunology suggest that the end of smallpox vaccination in the mid-20th century may have caused a loss of protection that contributed to the rapid contemporary spread of HIV. Raymond Weinstein, a family doctor turned laboratory scientist at George Mason University, Manassas, Virginia, USA, worked with a team of researchers from George Washington University and UCLA. The researchers looked at the ability of white blood cells taken from people recently immunised with vaccinia to support HIV replication compared to unvaccinated controls. They found significantly lower viral replication in blood cells from vaccinated individuals. Weinstein said, ‘There have been several proposed explanations for the rapid spread of HIV in Africa, including wars, the reuse of unsterilised needles and the contamination of ea
