United States regulators have for the first time approved a drug to prevent HIV infection.
The Food and Drug Administration said the drug Truvada, can be used by those at high risk of infection and anyone who may engage in sexual activity with HIV-infected partners.
Studies showed the drug reduced the risk of contracting HIV by up to 73 per cent.
There have been concerns the circulation of such a drug could engender a false sense of security and that it could result in a drug-resistant strain of HIV.
However, the FDA stressed that the drug should be used as part of a comprehensive HIV prevention plan, including condom use and regular HIV testing.