Characteristics of Human Immunodeficiency Virus (HIV) Seroconversions in a Large Prospective Implementation Cohort Study of Oral HIV Preexposure Prophylaxis in Men Who Have Sex with Men (EPIC-NSW)
Authors: Dharan Nila J , Jin Fengyi , Vaccher Stefanie , Bavinton Benjamin , Yeung Barbara , Guy Rebecca , Carr Andrew , Zablotska Iryna , Amin Janaki , Read Philip , Templeton David J , Ooi Catriona , Martin Sarah J , Ryder Nathan , Smith Don E , McNulty Anna , Brown Katherine , Price Karen , Holden Jo , Grulich Andrew E ,   Expanded PrEP Implementation in Communities in New South Wales (EPIC-NSW) research group, Guy Rebecca , Jin Jeff , Amin Janaki , Dharan Nila J , Zabloska Iryna , Vaccher Stefanie , Hammoud Mo , Chant Kerry , Holden Jo , Selvey Christine , Whittaker Bill , Schmidt Heather-Maire , Halliday Dale , Power Cherie , Price Karen , Parkhill Nicolas , Carr Andrew , McNulty Anna , Anderson Ben , Forssman Brad , Ooi Catriona , Carmody Christopher , Chanisheff Daniel , Baker David , Lewis David , Smith David , Templeton David J , Townsend David , Allen Debra , Smith Don E , Jackson Eva , Vlahakis Emanuel , Han Thai Gia , MacLeod Hugh , Lusk Josephine , Brown Katherine , Collins Kym , Bloch Mark , Ryder Nathan , Doong Nicolas , Read Phillip , Finlayson Robert , Martin Sarah J , Tuck Meng Soo Clara , Yeung Barbara , Ogilvie Erin , Cabrera Gesalit , Clackett Shawn , Vickers Toby , Smith Lucy Watchirs 
Published: August 2022

Abstract

Background
Most human immunodeficiency virus (HIV) seroconversions in people who have initiated preexposure prophylaxis (PrEP) occur in the context of insufficient adherence. We describe participants who seroconverted after being dispensed PrEP in a large PrEP implementation study in Australia.

Methods
Expanded PrEP Implementation in Communities in New South Wales was an implementation study of daily oral PrEP in individuals aged ≥18 years at high risk for acquiring HIV. HIV seroconversions were defined as a positive HIV test by either antigen, antibody, or detectable HIV viral load after enrollment. Insufficient adherence, measured by dispensing logs or participant self-report, was defined as &lt;4 PrEP doses per week.

Results
A total of 9596 participants were enrolled and dispensed PrEP between 1 March 2016 and 30 April 2018; 30 were diagnosed with HIV by 31 March 2019. The median (interquartile range [IQR]) age was 31 (25–38) years, all identified as male, 29 (97%) identified as gay or homosexual, and 20 (69%) lived in a postcode with a low concentration of gay male residents. The median (IQR) days from first PrEP dispensing to diagnosis was 409 (347–656). There was no evidence that participants who seroconverted had been sufficiently adherent to PrEP. Nineteen (63%) participants who seroconverted were diagnosed with chlamydia, gonorrhoea, syphilis, or new hepatitis C infection. One participant had resistance to emtricitabine (M184V mutation) at diagnosis.

Conclusions
Participants who seroconverted were insufficiently adherent to PrEP despite being at high risk for acquiring HIV. Understanding the reasons for poor PrEP adherence in individuals who subsequently acquire HIV is critical to improving PrEP effectiveness.