A recent study compared two daily pills to prevent HIV infection in women. The newer pill, called F/TAF (emtricitabine/tenofovir alafenamide), was tested against the standard pill, F/TDF (emtricitabine/tenofovir disoproxil fumarate). Both pills are taken once a day to reduce the risk of getting HIV. The study included 1,380 women in Uganda, Tanzania, and South Africa. Most of the women were cisgender and all were at risk for HIV.
Over 6 months, the researchers tracked how many women got HIV. In the group taking F/TAF, there were 3 infections out of 683 women. In the group taking F/TDF, there were 2 infections out of 697 women. This means the rate of new HIV infections was about 0.86 per 100 person-years for F/TAF and 0.56 per 100 person-years for F/TDF. These numbers are very close, suggesting both pills work similarly.
However, the study had a major problem: not enough women took the pills as directed. Only about 14% of women took 2-3 tablets per week, and only 9% took 4 or more tablets per week, based on blood tests. Because of this low adherence, the study did not have enough power to prove that F/TAF is just as good as F/TDF. The researchers could not show that F/TAF was "noninferior" (meaning not worse) than F/TDF.
The results are not strong enough to say one pill is better than the other. Both pills prevented HIV, but the study was too small and had too few people taking the pills regularly to draw firm conclusions. Other larger studies have shown that F/TAF works well for HIV prevention in both men and women, but this particular study could not confirm that.
For women considering PrEP, both pills are options. The newer pill F/TAF may have some advantages, like less effect on kidney and bone health, but this study did not look at those side effects. The main takeaway is that both pills can prevent HIV when taken consistently, but more research is needed to see if F/TAF is truly as effective as F/TDF in real-world settings.
In summary, this study found similar HIV infection rates with F/TAF and F/TDF, but low adherence and a small number of infections made it impossible to prove the newer pill works just as well. Women should talk to their doctor about which PrEP option is best for them, and remember that taking the pill every day is key to staying protected.
