The research could someday replace a daily pill taken to prevent infection with an injection given four times a year.
The long-acting drug was found to prevent the virus that causes AIDS in lab monkeys.
This has not yet been studied in humans but researchers suspect a quarterly or even monthly injection might help high-risk people comply with medication regimens.
In other health news, a new study suggests yoga can do more than just stretch the muscles.
Yoga may help breast cancer patients improve their chances of survival.
Researchers divided breast cancer patients undergoing radiation therapy into a yoga group, a simple stretching group, and a group that did neither one.
After six weeks, the yoga group had significantly less fatigue, pain and depression symptoms than the other participants.
But more importantly, those who did yoga had lower levels of the stress hormone cortisol which is linked to poor survival in breast cancer patients.
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