Those taking Truvada (emtricitabine/tenofovir) as pre-exposure prophylaxis (PrEP) are not at a major risk of developing resistance to the components of the drug should they seroconvert, aidsmap reports. There is a significant risk, however, if someone is experiencing acute HIV infection when he or she begins taking PrEP. Researchers published this analysis of data from the iPrEx study in the Journal of Infectious Diseases.

The iPrEX study, which first proved PrEP's efficacy, involved 2,451 participants who were equally randomized to receive either Truvada or a placebo. During the study, 141 participants seroconverted, including 10 people who had acute HIV infections that went undetected when they were randomized. Two of these people were in the treatment arm, both of whom developed resistance to emtricitabine.

Out of the 131 seroconversions that took place after randomization, 48 were in people in the treatment arm. None of them had resistance to the components of Truvada. Two of them did show minor variant emtricitabine-associated resistance, but both to a very low effect.

To read the aidsmap story, click here.

To read the study abstract, click here.