Estimating Prevention-Effective Adherence to HIV Pre-exposure Prophylaxis (PrEP) Among Australian Gay, Bisexual and Queer Men and Non-binary People: A Mixed-Methods Analysis

James MacGibbon; Anthony K J Smith; Timothy R Broady; Sarah K Calabrese; Jeanne Ellard; Dean Murphy; Tina Gordon; Simin Yu; James Gray; John de Wit; Martin Holt; Benjamin R Bavinton

doi:10.1007/s10461-025-04899-1

Estimating Prevention-Effective Adherence to HIV Pre-exposure Prophylaxis (PrEP) Among Australian Gay, Bisexual and Queer Men and Non-binary People: A Mixed-Methods Analysis

AIDS Behav. 2025 Nov 11. doi: 10.1007/s10461-025-04899-1. Online ahead of print.

Authors

James MacGibbon¹, Anthony K J Smith^{2

3

4}, Timothy R Broady², Sarah K Calabrese⁵, Jeanne Ellard⁶, Dean Murphy^{6

7}, Tina Gordon⁸, Simin Yu², James Gray^{9

10}, John de Wit¹¹, Martin Holt², Benjamin R Bavinton¹⁰

Affiliations

¹ Centre for Social Research in Health, UNSW Sydney, Sydney, NSW, Australia. j.macgibbon@unsw.edu.au.
² Centre for Social Research in Health, UNSW Sydney, Sydney, NSW, Australia.
³ School of Population Health, Curtin University, Perth, WA, Australia.
⁴ Collaboration for Evidence, Research and Impact in Public Health, Curtin University, Perth, WA, Australia.
⁵ Department of Psychological and Brain Sciences, George Washington University, Washington, DC, USA.
⁶ Australian Research Centre in Sex, Health & Society, La Trobe University, Melbourne, Australia.
⁷ School of Population Health, UNSW Sydney, Sydney, NSW, Australia.
⁸ New South Wales Ministry of Health, Sydney, NSW, Australia.
⁹ Health Equity Matters, Sydney, NSW, Australia.
¹⁰ Kirby Institute, UNSW Sydney, Sydney, NSW, Australia.
¹¹ Department of Interdisciplinary Social Science, Utrecht University, Utrecht, Netherlands.

PMID: 41214255
DOI: 10.1007/s10461-025-04899-1

Abstract
in English, Spanish

Oral HIV pre-exposure prophylaxis (PrEP) is highly effective when taken appropriately at times of HIV risk, termed "prevention-effective adherence". To understand suboptimal adherence, we refined a brief measure for surveys among gay, bisexual and queer men and non-binary (GBQ+) people. We used a mixed-methods design, comprising a national, online cross-sectional survey (June-July 2023) and cognitive interviews (August-October 2023). Logistic regression identified characteristics of PrEP users who reported condomless anal intercourse with casual partners (CLAIC) that was not protected by their own PrEP use because they missed PrEP doses ("PrEP-unprotected CLAIC"). Cognitive interviews investigated whether the prevention-effective adherence measure was comprehensible. Of 2,046 survey respondents, 792 current PrEP users who had CLAIC in the past 6 months were included (Median age = 37, 86.7% gay, 34.5% non-daily-PrEP users). Of PrEP users who reported any CLAIC, 194 (24.5%) reported any PrEP-unprotected CLAIC. They were more likely to: be < 30 years old, be born in Asia vs. Australia, be part-time vs. full-time employed, use non-daily PrEP, have recently initiated PrEP, have experienced side effects from PrEP, and report recent sexualized drug use. They were less likely to find it easy to get PrEP. The 14 interviewees asked about the survey items (Mean age = 33; 50% gay; ) were able to answer the questions and reliably interpret the content. This first national estimate of prevention-effective adherence found that 24.5% of PrEP users who had CLAIC reported any PrEP-unprotected CLAIC. Targeted interventions in subgroups with more frequent PrEP-unprotected episodes must address side effects and other adherence barriers.

La profilaxis preexposición oral (PrEP) es altamente eficaz cuando se toma durante períodos de riesgo de VIH, lo que se denomina adherencia efectiva para la prevención. Refinamos una medida breve de adherencia para encuestas en hombres gais, bisexuales, queer y personas no binarias (GBQ+), y evaluamos sus características asociadas con relaciones sexuales anales sin condón con parejas ocasionales (RSAO) no protegidas por PrEP. En una encuesta nacional en línea (junio-julio 2023), 792 personas usuarias actuales de PrEP que reportaron RSAO fueron analizadas. El 24.5% reportó al menos una RSAO no protegida por PrEP. Estas se asociaron con menor edad, nacimiento en Asia, empleo parcial, uso de PrEP no diaria, inicio reciente, efectos secundarios, consumo sexualizado de drogas y dificultades para acceder a PrEP. Entrevistas cognitivas (n = 14) confirmaron comprensión del ítem. Las intervenciones deben centrarse en barreras de adherencia y considerar formulaciones de PrEP de acción prolongada adaptadas a preferencias individuales.

Keywords: Attitudes; Australia; Gay and bisexual men (GBM); HIV prevention; Men who have sex with men (MSM); PrEP adherence; Prevention-effective adherence.

Abstract in English, Spanish

Abstract
in English, Spanish