The study was conducted in Mombasa, Kisumu, and Kiambu counties, where the key population mapping and size estimation performed by NASCOP in 2018 indicated a total of 2,855, 2,492, and 1,664 MSM, respectively ( National AIDS and STI Control Programme, 2019). According to a virtual mapping survey conducted in the same counties, 25% of MSM operated virtually rather than visiting actual physical locations to find sexual partners ( Emmanuel et al., 2020). As of July 2020, HAPA Kenya in Mombasa had registered 2,545 MSM, MAAYGO in Kisumu had registered 2,432 MSM, while MPEG in Kiambu registered 2,166 MSM. As per data from a polling booth survey conducted in 2017, the self-reported HIV prevalence among MSM was 19% in Mombasa, 13% in Kisumu, and 23% in Kiambu County ( National AIDS and STI Control Programme, 2018).

The conception and execution of the HIVST programme was guided by the 2017 HIV Self-Testing Guidelines, the 2018 Young Key Population Guidelines, and the 2014 Key Population Guidelines from NASCOP, which members of our team were instrumental in developing with the Ministry of Health of Kenya. The intervention, which began concurrently in all three sites between August 2019 and the end of July 2020, was integrated into already-existing HIV and sexual health programmes carried out by the three partner CBOs in their respective counties with the goal of reaching all MSM over the age of 15 ( Bhattacharjee et al., 2019).

To guide the design of the intervention, baseline quantitative and qualitative research was carried out. The HIVST implementation team, which included programme managers, programme officers, field officers, outreach workers and peer educators from the three CBOs were part of the intervention design with a focus on demand generation and mobilization, service provision, and connection to prevention and treatment-related services. Under the supervision of 19 outreach workers, a total of 161 peer educators were engaged in the intervention process as the main team. Each month, outreach workers, project staff, and regional field coordinators from PHDA met with the peer education teams in Mombasa, Kisumu, and Kiambu, numbering 63, 60, and 38 peer educators, respectively, to discuss the success of the interventions and to develop recommendations. The programme management team consisted of three study coordinators, five clinicians, four HIV testing services (HTS) counselors, and four monitoring officers.

MSM who test infrequently and non-testers were the main target groups for the distribution of HIVST kits. "Frequent testers" were defined as MSM who had an HIV test during the previous six months; "infrequent testers" were those who had an HIV test within the previous six to twelve months; and "non-testers" were MSM who had not had an HIV test within the previous twelve months.

Peer educators created demand for HIVST through hotspot-based peer connections, during key population drop-in centre (DIC) events at the organizations, and at promotional events for HIVST. Online demand creation was also utilized through channels such as Facebook, WhatsApp groups, and MSM-specific dating sites such as Grindr, Planet Romeo, and Hornet. Across the three sites, an average of 4,659 MSM were contacted each month from both physical and virtual venues. In order to create demand, health care providers in the three sites provided information about HIVST at the DICs and during clinical outreaches. The peer outreach workers also used physical and electronic posters with HIVST messages that highlighted the advantages of HIVST kits and provided access to more resources, as well as t-shirts, pamphlets, banners, aprons for bartenders, reflectors for riders' safety, and posters in the restrooms of club-based hotspots (see Figure 1– Figure 3).

A total of 18 social events were planned by peers across the sites, including DJ nights, MSM-themed parties, fun days (which featured social events like coffee dates, fashion displays, and grooming), World AIDS Day celebrations, and "Let's Get Real" PrEP-related gatherings. These events reached 3,227 MSM on average (78% from physical places; 22% from virtual spaces) with HIVST messages each month.

HIVST was made available to MSM in the three counties through two main delivery channels: (i) community-based delivery channels and (ii) facility-based delivery channels. A trained group of individuals, including clinicians, nurses, outreach workers, peer educators, and peers, delivered the kits. Along with the kits, the team provided information and education about sexuality, safer sex practices, HIV testing services, and prevention and treatment services to meet the needs of people who were not enrolled in programmes.

Community-based delivery channels . This approach saw HIVST kits being promoted and distributed by and within the MSM community. Within this channel of distribution, two methods were used to offer kits to the community . Direct methods entailed trained MSM peer outreach workers distributing HIVST kits directly to their peers during peer outreaches at hotspots, during events such as parties, clubs, and DIC gatherings. Indirect methods involved the distribution of kits through social and sexual networks, where peers who were offered HIVST kits could collect additional kits to offer to their networks. The goal of indirect distribution was to reach people who were not enrolled in or served by the programmes ( Bhattacharjee et al., 2019). The Kisumu site relied on peers described as "super mobilisers" (peers who were known to have extensive social and sexual networks) for distribution. Indirect distribution channels for MSM, additionally included delivery to peers' homes and the use of courier services, which was commonly used among virtual peers.

Facility-based delivery channels . This distribution channel aimed at offering HIVST kits within health care settings. MSM were able to obtain HIVST kits directly from key population programme clinics and DICs, including those integrated within government facilities. In these settings, health care providers offered HIVST kits to MSM during their routine visits to the clinics. MSM were provided with a dedicated room or space to perform the test or would otherwise be assisted by a health care provider or carry the kit home for later testing. Additionally, MSM were provided with HIVST kits during regularly organized clinical outreaches, which occurred in convenient locations, such as hotspots. In all cases, MSM were offered the choice of assisted (supported by outreach or clinical professionals) or unassisted (on their own) self-testing based on their preferences.

A coordinated follow-up system was put in place a few months into the intervention to efficiently help connect the recipients of HIVST kits to prevention and treatment services. For MSM who had consented to be followed, the clinical team (HTS providers and clinicians) made phone calls and sent text messages, with the assistance of peer educators. Peer educators and peers supported follow-up for MSM not consenting to be followed by health care providers. Referral cards with clinical contacts were given out along with HIVST kits so that participants could call or text the clinical team for more information or for referrals. To facilitate linkages to services, accompanied referrals were also offered.

The COVID-19 pandemic occurred during the intervention, necessitating a re-strategizing of the project. The team scaled up virtual demand generation through the use of virtual mobilization and online HIVST communication materials, such as short messages, videos, YouTube sensitizations, and Facebook DJ nights. Additionally, HIVST kits and HIV prevention commodities were delivered using motorcycles, mobile vans, door-to-door delivery, and courier services, along with messages promoting HIVST and COVID-19 prevention. HIVST kit distribution was expanded to include frequent testers who could not get to DICs or other health institutions for routine testing because of lockdowns and curfews. Follow up of HIVST users was intensified and any HIVST user experiencing symptoms such as fever, cough or difficulty in breathing were advised to seek medical care.

To evaluate the HIVST intervention, the research team employed a mixed-methods approach.

Longitudinal qualitative cohort: The longitudinal study assessed the effectiveness of different delivery mechanisms on improving the coverage and frequency of HIV testing. Community researchers developed a sampling plan to enroll 24 participants from each of the three sites. Participants were age 18 years and older, had sex with other men in the last 12 months, assigned male sex at birth, and willing to be followed over a period of one year for in-depth interviews at baseline, midline and at endline. Attention was paid to ensure representation of different ages, socio-economic status, and involvement in sex work, as well as experiences of MSM who were enrolled in CBOs compared to those who were not. Interviews were conducted by community researchers who underwent a four-day training workshop on research ethics ( Anderson, 2011) and qualitative research methods. Community researchers conducted the interviews in the language most comfortable to the participants in safe spaces run by the community-led organizations and in selected venues which were identified by the peer educators in consultation with the community and considered to be secure and MSM-friendly. Interviews lasted approximately an hour and were recorded, transcribed, and translated (where necessary). Seventy baseline, 36 midline, and 46 endline in-depth interviews were conducted with HIVST service users. Community researchers were then involved in participatory thematic analysis of the transcripts ( Kombo et al., 2023).

Meeting reports: Monthly routine monitoring reports using standard reporting tools were produced by the outreach and clinical teams and were analyzed at the site-level on a monthly basis, and shared with the implementation team to discuss areas for improvement. A more detailed analysis was conducted by the implementation team quarterly to assess emerging themes.

Polling booth surveys: In order to understand progress towards achieving the intervention's goals and to inform mid-course adjustments in the design of the intervention, we conducted a population-based quantitative assessment using a polling booth survey (PBS) at baseline and endline of the project, as suggested by Behanzin et al. (2013), and included further propositions on the study design according to Bhattacharjee et al. (2019). PBS operates as an anonymous group interview to minimize social desirability bias and offers a low cost and rapid assessment process.

The initial round of PBS was executed in Kiambu, Kisumu, and Mombasa in September 2019, with the endline surveys taking place in August 2020. These surveys were carried out by programme staff, outreach workers, and peer educators from three community-led CBOs, receiving technical and supervisory assistance from the NASCOP Technical Support Unit. Participants for the PBS were selected randomly by peer educators from a list of sampled physical and virtual hotspots. Participants were subsequently invited for interviews at venues determined through consultation with the peer educators. A significant proportion of the surveys took place within the secure settings of the DIC's safe spaces and board rooms, while the remaining interviews were conducted in safe and secure locations within hotspots, particularly for individuals located at a distance from DICs. The survey took around 45 minutes and collected information on the coverage and frequency of HIV testing and HIVST, the use of different delivery mechanisms, and linkages to prevention and treatment after testing, exploring questions, such as “Did you take an HIV test during the past 3 months? If yes, did you use HIV self-testing? Are you living with HIV? If yes, are you registered in an HIV care and treatment programme?”. In total, 1,497 participants participated in the PBS surveys at baseline and endline.

Additionally, we adopted Busza and colleagues’ process evaluation framework, previously used to evaluate an intervention for young women who sell sex in Zimbabwe ( Busza et al., 2016). Applying this framework to our data, we evaluated the fidelity (the degree to which the intervention was delivered as intended), feasibility (the difficulties encountered and how they were resolved), coverage (the degree to which the programme reached target participants), acceptability (participants' perceptions of the intervention), quality (how well the interventions were delivered), and effectiveness (did the intervention lead to change) of our HIVST programme.

Ethics approval was obtained from the institutional review boards of the Kenyatta National Hospital – University of Nairobi, Kenya (P557/08/2018) (December 6, 2018) and the University of Manitoba – Health Research Ethics Board, Canada (HS22205) (January 8, 2019).

Written informed consent was obtained from all participants prior to their participation in the study. Participants aged 15+ years were considered mature minors, in alignment with the national HIV testing guidelines ( National AIDS and STI Control Programme (NASCOP) & Kenya Medical Research Institute (KEMRI), 2015), which stipulate the minimum age for HIV testing without parental/guardian consent as 15 years and approved by ethics boards in Kenya and Manitoba.

In each site, an average of 793 MSM received 1,041 HIVST kits per month during the course of the 12-month intervention of which 86% and 14% were distributed through community and facility channels, respectively. Sixty-seven percent of the kits were given to infrequent testers and non-testers. In total, 3,989 MSM visited the clinic for prevention and treatment services for follow-up during the intervention period. In the section below, findings are examined using the process evaluation framework developed by Busza et al. (2016) in order to better understand the programme's results (summarized in Table 1).

The process evaluation showed fidelity to demand generation, service delivery, and linkage to prevention and treatment activities and timelines prior to the COVID-19 pandemic. HIVST was effectively communicated to MSM from both physical hotspots and virtual platforms thanks to the participation of both types of peer educators. The approaches used for creating demand were successful in encouraging the use of HIVST kits. While the promotional messages emphasizing the simplicity of HIVST were successful, participants shared that they found them to be a little too repetitive, especially for the virtual mobilization. Although infrequent and non-testers were the target MSM sub-populations for HIVST, COVID-19 shifted focus to also include frequent testers.

Prior to the intervention, all teams received training to support the successful rollout of the intervention ( Kombo et al., 2023). Peers raised concerns surrounding confidentiality, including how the project staff would be able to follow-up with HIVST users for prevention and treatment while maintaining confidentiality. As a result, each of the three participating sites built a central follow-up mechanism. The clinical team was entrusted with monitoring all willing users of the HIVST kit. The peer educators reported that, men who had not declared their MSM status were more hesitant to visit the clinic after testing because they feared being identified as MSM.

Based on the intervention's design and the national HIV testing protocol, confirmatory testing was only necessary for participants who received reactive results from an HIVST. However, there were instances where a few participants with non-reactive results insisted on being re-tested. The peer educator and outreach teams provided ongoing education to instill confidence in HIVST users. In the in-depth interviews, reasons expressed for not using the kits included low risk perception, fear of results, a lack of knowledge about HIVST, lack of faith in oral kits that don't require blood, and a preference for facility-based testing and physicians. The tracking of secondary distribution was mentioned as another difficulty. Peer educators distributed kits to their peers for secondary distribution and promoted secondary distribution as a way for people to learn their HIV status. However, receiving feedback from MSM who obtained HIVST kits via secondary distribution routes remained an ongoing challenge. Peers attempted to track and follow-up with their networks and encourage them to access prevention or treatment options after testing.

Some participants stated that during the pandemic, access to kits was hampered by COVID-19 control measures, as well as by the dread of numerous stressors brought on by pandemic-related interruptions. In order to maintain continuity in the provision of services to the community, "cyber-peer educators" replaced one-on-one peer educators in online sessions. During the pandemic, difficulties included some peer educators leaving the city and being unable to return for months, which had an adverse effect on the distribution of HIVST and routine testing.

A total of 8,764 MSM utilized HIVST, of whom 3,569 were from Mombasa, 2,080 from Kiambu, and 3,115 from Kisumu. One-fourth of these men were connected to the intervention through online communities. With the exception of the COVID-19 period, when frequent testers were also given HIVST kits, infrequent and non-testers were the major target population for HIVST kit distribution. Distribution of 67% of the kits went to infrequent testers and non-testers.

MSM demonstrated a good opinion of the intervention through their active participation in the project. MSM-led CBOs were in control of the intervention, therefore they took a leading role in its conception, implementation, monitoring, and evaluation. As a result, the project fostered a sense of communal ownership and responsibility.

The analysis of the in-depth interviews revealed that the participants had a favorable opinion of the intervention. Participants, including those who did not use HIVST kits, expressed that they were aware of HIVST and had learned about it from peer educators, social media, and the DICs. The majority of participants during the COVID-19 period said that they continued to get information via social media (such as WhatsApp groups and Facebook pages) in the form of demonstration films and details on where to get kits. A significant number of participants thought the material was good and conveyed well, although some thought peer educators were less able to give precise details on linkages following testing. There were recommendations for further training of peer educators in effective linkages and referrals.

Additionally, more MSM who used HIVST tested regularly than those who did not use HIVST at the study's endline. According to the PBS findings, 82% of HIVST users had a recent test during the last three months, compared to 58% of non-users. Since HIV test results are confidential, the participants regarded HIVST as a way to decrease the number of men in their community who do not know their HIV status and link them to treatment.

The majority of participants admitted to feeling anxious about using the kits for the first time. Numerous factors, including the fact that HIVST was a novel technique, contributed to their unease.

However, initial apprehension and worry subsided over time, and the majority of participants grew accustomed to using the kits and described it as a straightforward technology.

In the polling booth survey, over one-third of participants (34%) said they would prefer HIVST, even though 57% of individuals continued to choose rapid HIV testing the next time they tested. Preferences for HIVST included the capacity to maintain anonymity and increase choice, the convenience it provided under COVID-19 constraints, and its utility for secondary distribution and partner testing, as expressed in the quotations below:

At the endline, the PBS data showed prevention services had reached 90% of participants who had ever used HIVST, compared to 76% of people who had never used HIVST. At endline, 84% of participants had been linked to care and treatment with significant improvement among virtual peers from 71% at baseline to 93% at endline. Even during COVID-19, when CBO/DIC visits were low, the majority of participants described the peer educator's role in routine follow-up as one of continual emotional support and as an essential component of community-based care.

Effectiveness. When compared to baseline, the PBS data showed that the total uptake of HIVST rose noticeably at endline. At endline, 47% of MSM from both physical and virtual sites reported using HIVST in the previous three months (31% at baseline). Virtual peers showed significant improvement, increasing from 25% to 51% at baseline and endline, respectively. With an overall rise from 63% of MSM getting treatment in the past three months at baseline to 73% at endline, access to services from the project intervention also demonstrated an improvement. As the proportion of people living with HIV rose from 13% at baseline to 19% at endline, the intervention also resulted in new diagnoses.