Scientists recently set out to estimate what antiretroviral drug concentration in the blood cells of men who have sex with men was associated with a 90 percent reduction in HIV infection risk, and how many Truvada doses per week would achieve that concentration. They found that to achieve the 90 percent risk reduction, the men needed to take Truvada at least 4 days per week (achieving a concentration of roughly 16 x 10-15 moles of tenofovir diphosphate per million blood cells). These results could open the door to the exploration of ways to optimize PrEP dosing.
Learn more about this study.