Insights from the Engage Study: The road to elimination of HIV as a public health threat for gay, bisexual and other men who have sex with men


Recently released estimates from the Public Health Agency of Canada show significant progress toward eliminating HIV as a public health threat for gay, bisexual and other men who have sex with men (gbMSM). The estimated rate of new infections among sexually active gbMSM decreased by 20% from 2018 to 2020, which is a huge cause for celebration.

Also encouraging are the estimates from 2017-2019 data that show 98% of gbMSM living with HIV in Canada had been diagnosed, 96% of those diagnosed were on treatment, and 94% of those on treatment had achieved viral suppression. Viral suppression means that the amount of HIV in their blood is so low that they cannot pass it on to their sexual partners. These estimates reveal that UNAIDS targets for 2025 (95-95-95) are now within arm’s reach for gbMSM in Canada.  

Although these numbers are promising, we mustn’t forget that gbMSM in Canada still bear a hugely disproportionate burden of HIV – over 45% of new HIV infections in 2020, despite only representing an estimated 4% of the adult male population in Canada. In order to address this unacceptable situation, we need solid data – not just about broad targets, but also about gaps in prevention, testing, treatment and other services.

The Engage Study

The Engage Study was initiated in 2017, in part to help identify and understand gaps in HIV service provision among gbMSM. Engage is a multi-year sexual health cohort study that relies on social networks to recruit participants in Toronto, Montreal and Vancouver. Participation involves regular testing for sexually transmitted and blood-borne infections (STBBIs) and a self-administered survey assessing factors that may influence participants’ sexual health.

A central goal of Engage is to provide up-to-date estimates of HIV and STBBI prevalence and incidence (new infections) among gbMSM. Engage also collects and analyses data on a wide array of indicators across prevention, testing, treatment and sustained viral suppression. Several insights from this research are shared below, which can help us understand what still needs to be improved, how to make these improvements and for whom. This is invaluable as we keep the target of HIV elimination in our sights.

Prevention: PrEP uptake

PrEP (pre-exposure prophylaxis) is a proven, highly effective method of HIV prevention that involves an HIV-negative person taking HIV medications to reduce the risk of HIV infection. However, one Engage analysis suggests that uptake has been low among the men who could benefit from it most. The majority of Engage participants who met the clinical recommendations for PrEP use reported being aware of PrEP, but only about half of them had felt the need to use it over the previous six months. Even fewer (about a quarter) had tried to access it. And when we get down to the critical question of how many participants meeting the clinical recommendations used PrEP, our estimate is around 15-20%. Among gbMSM nationally, these numbers are probably lower still because Engage participants were all from major urban centres with relatively high concentrations of HIV-related resources and services.  

Engage analyses have yielded insights into why many men seem not to be using PrEP even when they meet clinical recommendations. One factor may be lack of knowledge about PrEP, its effectiveness and when or for whom PrEP is recommended. Engage participants who didn’t use PrEP, despite meeting the clinical recommendations, were more likely to say they don’t know enough about it. They were also more likely to say they don’t think PrEP is effective. This is despite the fact that a strong body of evidence has shown that PrEP is effective.

Participants not using PrEP were also more likely to report not feeling at high enough risk to use it, even though, again, for this analysis they all met the clinical recommendations. They were also more likely to be in a relationship with a main sexual partner. This might also suggest lack of knowledge about when PrEP is recommended, for instance, if their partner’s HIV status is unknown.                   

Another factor that may help explain low PrEP uptake is the absence, or perceived absence, of safe healthcare spaces to openly discuss sexual health and HIV prevention options. Participants not using PrEP were more likely to report that they could not find an accepting doctor who would prescribe PrEP. They were also less likely to disclose that they had male sexual partners to a primary care provider. These findings remind us that stigma and discrimination are still powerful obstacles to effective action on HIV. There is still a great need to make healthcare spaces safer and less stigmatizing for gbMSM, to foster open and frank discussions of sexual health and HIV prevention.

Testing: Reaching the undiagnosed

As mentioned above, major progress has been made ensuring gbMSM living with HIV know their status. Engage estimates suggest that the UNAIDS target of diagnosing 95% of people living with HIV by 2025 has already been surpassed among gbMSM in Toronto, Montreal and Vancouver. However, there’s still room for improvement. A small but significant number of men in all three cities who reported their HIV status as negative or unknown had never been tested for HIV (prior to the study). This number was highest in Vancouver at 18.6% (compared to 12.9% in Toronto and 11.5% in Montreal). This is somewhat surprising, given comprehensive efforts in Vancouver and throughout British Columbia like STOP AIDS and treatment as prevention advocacy.

This illustrates the fact that, even amid extensive, multi-pronged strategies, some gbMSM can fall through the cracks. It also reinforces the importance of researching why some men haven’t been tested and working out how to engage them. The findings also reinforce the importance of making testing as easy, accessible and stigma-free as possible.

Treatment: Achieving viral suppression

We’ve come a long way toward ensuring all gbMSM living with HIV start and stay on effective treatment. Engage estimates show a high level of engagement in HIV care among gbMSM in Toronto, Montreal and Vancouver. But there is still work to be done. A good place to start is by focusing on suppressed viral load­ – the only UNAIDS target we haven’t yet reached for this group. Engage estimates for viral suppression are good overall but, again, they leave room for improvement. Identifying why some men may struggle more than others to reach and maintain viral suppression is critical.

Findings from Engage help shed light on this. For example, the study revealed that younger participants were less likely to have a suppressed viral load. This could be partly the result of lower retention in care, which has been linked elsewhere to both younger age and reduced viral suppression. The study also found that those without a consistent primary care provider were more likely to be unsuppressed. Both findings remind us of primary care’s critically important role in delivering and coordinating HIV treatment. They highlight the need to improve health care accessibility and continuity, particularly for men whose life circumstances (temporary or ongoing) make consistent care and sustained treatment adherence a challenge.

Thanks to insights from the Engage study, we have a clearer picture of who isn’t being reached by HIV services and what we can do to facilitate access to HIV services. These gaps reveal where we need to improve our response so we can avoid backsliding on achievements and continue to progress towards our goal of eliminating HIV as a public health threat.


Trevor Hart, PhD, is the director of the HIV Prevention Lab, where he studies why gay, bisexual and queer men are at higher risk for HIV and other sexually transmitted infections, as well as explores new forms of counselling and psychotherapy that promote their mental and sexual health. Hart is also director of Toronto Metropolitan University’s HOPE Centre for Gender and Sexual Minority People, which focuses on understanding and promoting health outcomes for LGBTQ2S+ people. He is a practising psychologist with a small private practice.

Dan Miller is CATIE’s knowledge specialist, HIV care and STI. He has a master’s degree in public health from the University of Toronto and previously worked in health services research in Toronto’s academic health sciences system.


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