Truvada helps block HIV's ability to attach to healthy cells and start the infection. (Wikimedia Commons)

Although the pill had previously been approved for treatment of the HIV infection, clinical studies now show the drug, known as Truvada, can also serve as a source of protection for uninfected high-risk people, such as sex workers and those with an infected partner, if taken daily pre-and-post-exposure.

A 2010 study showed Truvada reduced HIV infection by 75 percent in heterosexual couples, where one couple was infected and the other was not. Experts said the approval could help slow the spread of HIV, which "has held steady at about 50,000 new infections per year for the last 15 years." 

Truvada is considered both a breakthrough and a danger on the HIV/AIDS front. Some health experts believe using Truvada for prevention "will foster a false sense of security among users, leading people to believe mistakenly that they are immune to the virus and reduce their use of condoms."

FDA experts responded to such concerns and said there was no indication that Truvada users in clinical trials were more likely to engage in risky sexual behavior.

Read the full story at TIME and MSNBC.

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