Prostitutes lose HIV immunity
A group of prostitutes thought to be immune to HIV have now become infected, causing dismay to scientists hoping to develop an AIDS vaccine.
It was thought that exposure to HIV on a regular basis created immunity, but six Kenyan women previously thought to be resistant are now HIV-positive.
The women are all former prostitutes who have since left the business.
Scientists now think immunity may be reliant on continued exposure - once regular contact with HIV stops, immunity is lost.
Researchers at Oxford University have been monitoring 43 Kenyan prostitutes constantly exposed to HIV who had not been infected.
bbc
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