PrEP, or pre-exposure prophylaxis, has become an increasingly popular method of preventing HIV infection.

But what happens if someone taking PrEP tests positive—either because they were infected before starting their regimen, or they took the medication improperly. Could the drugs interfere with the efficacy of treatment for HIV?

To find out, researchers followed nine patients who had drug-resistant strains of HIV.

A study published in the journal AIDS revealed that tests performed six months after seroconversion—and the discontinuation of PrEP—failed to find any drug-resistant strain of the virus.

Follow-up testing one year and two years later seemed to confirm that the resistance was related to the use of PrEP, as it fell to undetectable levels for all the subjects once they ceased.

"Multiple studies have now shown that the risk of developing resistance from PrEP is very low, but is an important concern for those who initiate PrEP during unrecognized acute infection," researchers wrote.

"Our data show that resistance selected in these cases decays rapidly to levels below detection of even highly sensitive assays."

h/t: Washington Blade