What are the situational and behavioral factors associated with condomless anal sex without pre-exposure prophylaxis in MSM?

Patterns of PrEP and condom use among PrEP users in Belgium: a web-based longitudinal study

BACKGROUND

Tailoring pre-exposure prophylaxis (PrEP) service delivery is key to scaling-up PrEP uptake. Optimal implementation of tailored services requires, among other things, insights into patterns of PrEP use, sexual behaviours and condom use over time.

METHODS

Between September 2020 and January 2022, we conducted a web-based, longitudinal study among PrEP users in Belgium. In three questionnaire rounds every six-months, we assessed PrEP and condom use, and sex with steady, casual and anonymous partners in the preceding three months. Based on the patterns of PrEP use in the preceding three months, we identified distinct PrEP use categories. We investigated differences in baseline socio-demographics and sexual behaviours by PrEP use category using Fisher's exact and one-way ANOVA tests. Patterns in PrEP and condom use over time were examined using descriptive analyses and visualised in alluvial diagrams.

RESULTS

In total, 326 participants completed the baseline questionnaire, and 173 completed all three questionnaires. We identified five distinct PrEP use categories: daily (≥ 90 pills), almost daily (75-89 pills), long period (> 7 consecutive days and < 75 pills) with or without additional short period use, short period (1-7 consecutive days and < 75 pills) and no PrEP use (0 pills). During the study, percentages of individuals in each PrEP use category varied, but did not change significantly over time. At baseline, daily and almost daily users were more likely to report five or more casual sex partners, ten or more anonymous sex partners and anal sex on a weekly basis with casual or anonymous partners compared to those using PrEP for long or short periods. Up to 12.6% (n = 16/127) of participants reporting anal sex with casual or anonymous partners, indicated always using condoms and PrEP with these partners. One in three (n = 23/69) participants who reported anal sex with steady partners had condomless anal sex and did not use PrEP with these partners; with casual or anonymous partners less than 3% reported this.

CONCLUSIONS

Our findings show that there is little variation in PrEP use over time and that PrEP use was associated with sexual behaviours, which could be taken into account when designing tailored PrEP care.

Dynamic immune markers predict HIV acquisition and augment associations with sociobehavioral factors for HIV exposure

Prior studies attempting to link biomarkers of immune activation with risk of acquiring HIV have relied on cross sectional samples, most without proximity to HIV acquisition. We created a nested case-control study within the Sabes study in Peru, and assessed a panel of plasma immune biomarkers at enrollment and longitudinally, including within a month of diagnosis of primary HIV or matched timepoint in controls. We used machine learning to select biomarkers and sociobehavioral covariates predictive of HIV acquisition. Most biomarkers were indistinguishable between cases and controls one month before HIV diagnosis. However, levels differed between cases and controls at study entry, months to years earlier. Dynamic changes in IL-2, IL-7, IL-10, IP-10 and IL-12, rather than absolute levels, jointly predicted HIV risk when added to traditional risk factors, and there was modest effect modification of biomarkers on association between sociobehavioral risk factors and HIV acquisition.

Factors Associated with Unprotected Anal Sex among Men Who Have Sex with Men in Mexico

The global prevalence of HIV is notably higher in men who have sex with men (MSM) compared with other male populations. Unprotected anal intercourse is the riskiest sexual behavior for HIV acquisition and/or transmission among this minority population. The purpose of the study was to identify if the syndemic of psychosocial stressors and experienced stigma are predictors of unprotected anal sex in Mexican MSM. A cross-sectional analytic study was carried out. It included adults residing in Manzanillo, Mexico, with oral/anal sex practices within the last year. Informed consent was given by 142 participants selected using snowball sampling. Collected data included sociodemographic characteristics, psychosocial stressors, experienced stigma, HIV knowledge, knowing a friend/acquaintance living with HIV/AIDS, and sexual risk behaviors. Adjusted logistic regression was used to identify predictors of unprotected anal sex within the last six months. Presence of syndemic of psychosocial stressors, drug use during sex, having friends/acquaintances with HIV/AIDS, and experiencing high stigma were positively associated; high level of HIV knowledge was negatively linked. Reducing psychosocial stressors and integrating stigma-mitigation strategies are key elements to reduce HIV transmission.

PrEP in the Context of Other HIV Risk Reduction Strategies Among Men Who Have Sex with Men: Results from the Flash! PrEP in Europe Survey

Combination HIV prevention covers a range of biomedical, behavioral, and socio-structural interventions. Despite the growing availability of pre-exposure prophylaxis (PrEP), it is not always accessible in European Centre for Disease Prevention and Control reporting countries and may not meet the needs of all at-risk populations. Based on the Flash! PrEP in Europe data, multiple correspondence analysis and hierarchical clustering were used to identify patterns in HIV prevention strategies among 9980 men who have sex with men (MSM). PrEP interest was evaluated among four identified clusters: (A) "high condom use, sometimes Treatment as Prevention (TasP)"; (B) "mix of methods, infrequent condom use"; (C) "high condom use, tendency to choose partners based on serological status" and (D) "moderate use of condoms mixed with other prevention strategies". Clusters B and D had higher PrEP interest. These results suggest that MSM use a range of behavioral and biomedical risk reduction strategies that are often combined. On-demand PrEP may meet the needs of MSM who infrequently use condoms and other prevention methods.

Daily Associations Among Alcohol Intoxication, Partner Familiarity, Participant Effortful Control, Urgency, and PrEP Uptake on Sexual Behavior in Men Who Have Sex with Men

The purpose of this study was to examine the effects of alcohol intoxication and its interaction with contextual or situation (partner familiarity) and individual differences variables (effortful control, urgency, and whether taking pre-exposure prophylaxis (PrEP) medication) on sexual behaviors in men who have sex with men (MSM), a subgroup for whom HIV continues to be a major public health problem in the U.S. The participants were 236 men recruited from two northeastern U.S. cities and aged 21-50 years, M = 27.8). These men participated in a 6-week (two 3-week sampling bursts) experience sampling method (ESM) study. The ESM data were collected via use of software installed on the participant's own or study-provided mobile phone. Individual differences variables were measured by participants' completing questionnaires measuring effortful control and urgency, and the participant's self-report of whether he was currently taking PrEP. The ESM data pertained to sexual behavior as well as situation variables of familiarity of relevant sexual partners and number of standard alcohol drinks consumed. The results generally were consistent with hypotheses, as alcohol intoxication showed a curvilinear relation to the occurrence of condomless anal intercourse. Furthermore, the likelihood of occurrence of condomless anal sex increased with increased familiarity of the sexual partner. Similarly, taking PrEP increased the likelihood of occurrence of condomless anal sex. At the same time, alcohol's effects were moderated by all three individual differences variables as expected, but the prediction that partner familiarity would moderate alcohol's effects on the occurrence of condomless sex was not supported. Clinical implications of the findings center on the application of the data to HIV prevention programs toward inclusion of more empirically supported, nuanced information on the relation between acute alcohol intoxication and sexual behavior. Directions for further research address the need for additional testing and refinement of a person × situation approach to alcohol and sexual behavior. Furthermore, it is argued that it is important to refine further the concept of sexual risk in the context of taking PrEP and to conduct more detailed, multivariate studies of the relation between taking PrEP and patterns of sexual behavior.

Adherence to event-driven HIV PrEP among men who have sex with men in Amsterdam, the Netherlands: analysis based on online diary data, 3-monthly questionnaires and intracellular TFV-DP

INTRODUCTION

Event-driven pre-exposure prophylaxis (edPrEP) with oral tenofovir disoproxil fumarate (TDF)/emtricitabine (FTC) is highly effective for preventing HIV acquisition in men who have sex with men (MSM) and is preferred over daily PrEP by some MSM. However, it is largely unknown how well MSM adhere to edPrEP. We then aimed to assess PrEP protection during CAS among MSM using edPrEP and participating in the Amsterdam PrEP demonstration project (AMPrEP).

METHODS

We analysed data from participants enrolled in AMPrEP who were taking edPrEP. We measured adherence through (1) a mobile application in which sexual behaviour and PrEP-use were recorded daily, (2) three-monthly self-completed questionnaires and (3) dried blood spot (DBS) samples collected around six, twelve and twenty-four months after PrEP initiation. We assessed the proportion of days with condomless anal sex (CAS) acts that were protected by PrEP, per partner type (i.e. steady partners, known casual partners, unknown casual partners), and the proportion of three-month periods during which PrEP was correctly used. Intracellular TFV-diphosphate (TFV-DP) concentrations were determined from DBS. Good adherence was defined as at least one tablet before and one tablet within 48 hours after a CAS act.

RESULTS

Between 11 September 2015 and 6 October 2019, 182 of 376 MSM (48.4%) used edPrEP for at least one three-month period. Of the 8224 CAS days that were reported in the app during edPrEP-use, we observed good protection for most CAS days involving steady partners (n = 1625/2455, 66.9%), known casual partners (n = 3216/3472, 92.6%) and unknown casual partners (n = 2074/2297, 90.3%). Men reported consistently correct PrEP-use in 851 (81.4%) of the 1046 three-month periods of edPrEP-use. The median TFV-DP concentration was 591 fmol/sample (interquartile range = 270 to 896).

CONCLUSIONS

Adherence to edPrEP was high as determined from the online app and questionnaire. DBS measurements were consistent with two to three tablets per week on average.

Coverage of Sex Acts by Event-Driven Pre-exposure Prophylaxis: A Sub-Study of the ANRS IPERGAY Trial

We assessed the coverage of sex acts by event-driven pre-exposure prophylaxis (ED-PrEP) over a 2-month period in 54 participants in the open label phase of the ANRS Ipergay trial. Participants received an electronic monitoring system device to record bottle openings. Self-questionnaires collected daily information on PrEP intake and sexual behavior. Intake was also estimated through returned pill counts. Full coverage of sex acts was defined as at least one pill taken both within 24 h before and within 48 h following sex. There was a strong correlation (r =  - 0.92) between the number of bottle openings and returned pill counts. During the study, 42 participants (78%) practiced ED-PrEP and 12 (22%) daily PrEP with bottle openings at least 5 days/week whatever their sexual activity. Out of the 154 reported receptive anal sex acts, 81% were condomless: among them, PrEP coverage was hight: 97% among those practicing daily PrEP and 82% among those using ED-PrEP.