Ending smallpox vaccination programmes may have contributed to the global spread of HIV/Aids, research has suggested.
A study published in the journal BMC Immunology found the vaccine may have offered protection to people in the epidemic’s early days.
The substance worked by producing a five-fold reduction in the ability of the virus to reproduce in the body’s white blood cells, said Dr Raymond Weinstein, from George Mason University in Mannasas, Virginia.
He added: “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 early batches of polio vaccine. However, all of these have been either disproved or do not sufficiently explain the behaviour of the HIV pandemic.
“Our finding that prior immunisation…may provide an individual with some degree of protection to subsequent HIV infection suggests that the withdrawal of such vaccination may be a partial explanation.”
Smallpox immunisation was phased out between the 1950s and 1970s as the disease became increasingly less common. HIV infection rates have since soared.
Copyright Press Association 2010