11 May 2012 Last updated at 03:27 ET
A panel of US health experts (click here for video) has for the first time backed a drug to prevent HIV infection in healthy people.
The panel recommended US regulators approve the daily pill, Truvada, for use by people considered at high risk of contracting the Aids virus.
Dr Robert Grant, from Gladstone Institutes, said regular use of the drug made protection from HIV infection much higher.
An ounce of prevention is worth...lives saved, quality of life insured and savings in the billions $US of treatment, there is no cure.
The period of acute HIV infection (AHI) (click here) is a relatively brief window of time -- roughly 10 weeks after initial infection -- but its impact on the spread of HIV may be very significant. During this early period, which likely continues through the first six months of infection, that people are considerably more infectious to others than at other stages of infection.
