A major concern for PrEP use is possible induction of drug resistance by prescribing PrEP to persons with undiagnosed HIV infection. Such persons may not have been screened appropriately for HIV or may have been screened during the window period between HIV exposure and infection. However, no data are available to determine the frequency of this phenomenon.
Using data from cases assigned for partner services from November 2015 to August 2017, we examined the viral resistance profile of recently diagnosed persons (< 12 months) in New York City (NYC) with a recent history of PrEP use to determine rates of mutations to PrEP component medications: emtricitabine (3TC) (M184I/V/IV/MV) and tenofovir disoproxil fumarate (TDF) (K65R). We compared acute HIV infection (AHI), negative NAAT, and prevalence of viral resistance in pre-diagnosis PrEP users and those with no PrEP use (never-users).
In this period, 95 (3%) out of 3,721 persons with a recent HIV diagnosis assigned for partner services had a report of pre-diagnosis PrEP use. Median duration of PrEP exposure before diagnosis was 3 months (IQR=7). Pre-diagnosis PrEP users were more likely than never-users to have a negative NAAT pre-diagnosis (33% vs 4%, p<0.0001), and were more likely to be diagnosed with AHI (33% vs 9%, p<0.0001). Genotypes were available for 75% of pre-diagnosis PrEP users and 62% of never-users. M184I/V/IV/MV was significantly more prevalent among pre-diagnosis PrEP users than never-users (26% vs 2%, p-value <0.0001). K65R mutations were found in 4 persons; none were pre-diagnosis PrEP users.
In a study of recently HIV diagnosed people from NYC, persons with a history of pre-diagnosis PrEP use were significantly more likely to have resistance mutations to 3TC. There were no signature TDF mutations (K65R) detected among pre-diagnosis PrEP users. In addition, persons with a history of PrEP were significantly more likely to have AHI leading to diagnosis. The latter may be due to an effect of the PrEP or the possibility that persons receiving PrEP are more likely to be receiving health care more regularly. Only one-third of pre-diagnosis PrEP users had evidence of a negative NAAT. Our findings stress the importance of screening regularly to reduce the likelihood of PrEP start during undetected HIV infection in order to reduce the risk of inducing drug resistance.