The worldwide eradication of smallpox may, inadvertently, have helped spread HIV infection, scientists believe.
Experts say the vaccine used to wipe out smallpox offered some protection against the Aids virus and, now it is no longer used, HIV has flourished. The US investigators said trials indicated the smallpox jab interferes with how well HIV multiplies, BBC News informs.
Such vaccination could have kept HIV transmission partially under control in the early days of the outbreak, which is thought to have begun in the 1950s, but withdrawal of the smallpox vaccine, called vaccinia, starting at about the same time might have freed HIV to spread unfettered, the researchers said.
The results are preliminary and it is "far too soon to recommend the general use of vaccinia immunization for fighting HIV," said one of the researchers, Raymond S. Weinstein of the biodefense program at George Mason University's Prince William campus in Manassas, Washington Post reports.