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  Conference on Retroviruses
and Opportunistic Infections
Seattle, Washington
March 4-7, 2019
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One in 50 in NYC with recently diagnosed HIV used PrEP in preceding months
  Conference on Retroviruses and Opportunistic Infections (CROI), March 4-7, 2019, Seattle
Mark Mascolini
Among 3685 people recently diagnosed with HIV in New York City, 91 (2%) used PrEP in the months before HIV diagnosis and so may have taken tenofovir/emtricitabine (TDF/FTC) in the early days of HIV infection [1]. Researchers detected mutations conferring resistance to FTC in almost one third of the prediagnosis PrEP group, but the hallmark TDF-related mutation emerged in no tested samples.
Prescribing PrEP to a person with undiagnosed HIV poses a risk that virus resistant to the PrEP drugs FTC and TDF will emerge. That scenario may occur because PrEP candidates may not be adequately screened for HIV or they may start PrEP during the window between HIV exposure and established infection. Giving the nucleic acid amplification test (NAAT) to PrEP candidates negative for HIV antibody can cut the risk of starting PrEP in a person during the undiagnosed phase of HIV infection. New York State recommends NAAT for people with symptoms of acute HIV infection or with a negative HIV antibody test but reported condomless sex in the past 4 weeks.
New York City Department of Health and Mental Hygiene (DHMH) researchers conducted this study to chart prevalence of resistance to PrEP drugs in people with pre-HIV diagnosis PrEP use. To identify such PrEP users the DHMH team scoured records from HIV Partner Services, medical providers, and NYC Surveillance Field Investigations. They figured prediagnosis PrEP prevalence in people diagnosed with HIV in the past 12 months and assigned partner services.
Among 3685 people diagnosed with HIV in the past 12 months during 2015-2017, the researchers identified 91 prediagnosis PrEP users (2%). Median PrEP duration before HIV diagnosis stood at 106 days (3.4 months), and median time between starting PrEP and HIV diagnosis measured 250 days (8.1 months).
Compared with recently diagnosed people who never used PrEP, those who did were more likely to be white (41% versus 14%), younger than 30 (58% versus 37%), cis-men (92% versus 76%), and men who have sex with men (89% versus 66%) or with a transgender sexual contact (6% versus 3%).
Three quarters of prediagnosis PrEP users and 63% of never-PrEP users had resistance genotypes available. Genotyping detected M184 mutations, which confer resistance to FTC, in 29% of the prediagnosis PrEP group versus 2% of the never-PrEP group. The hallmark K65R TDF-related mutation appeared in no samples of the prediagnosis PrEP group.
One third of prediagnosis PrEP users had acute HIV infection, compared with 9% of never-PrEP users. Only 5 of 91 PrEP users (5%) had a negative NAAT in the 0- to 2-day window before starting PrEP, a result suggesting infrequent NAAT use in PrEP screening.
The researchers stressed that "rigorous screening that includes NAAT is critical and can reduce PrEP initiation during undetected HIV infection." They also underlined the importance of routine resistance genotyping at HIV diagnosis in recent PrEP users. On the plus side, the NYC team noted that PrEP users have a better chance of early HIV diagnosis than others because they are more likely to receive regular health care.
1. Misra K, Jamie Huang J, Daskalakis DC, Udeagu CC. Impact of PrEP on drug resistance and acute HIV infection, New York City, 2015-2017. Conference on Retroviruses and Opportunistic Infections (CROI). March 4-7, 2019. Seattle. Abstract 107.