US approves Gilead's twice-yearly injection to prevent HIV

Despite the impressive results, optimism may be tempered by the drug's cost. [AFP]

Drugs to prevent HIV transmission, known as pre-exposure prophylaxis or PrEP, have existed for more than a decade. But because they typically require taking a daily pill, they have yet to make a significant dent in global infections.

"This is a historic day in the decades-long fight against HIV," Gilead chairman and chief executive Daniel O'Day said in a statement.