Table 3.

Study measurements and main findings

First author, year	PrEP use measurement	Social support measure	Analytic methods	Main findings
Bonett, 2022 [42]	PrEP continuum: (1) PrEP unaware, (2) PrEP aware but unwilling to use, (3) PrEP aware and willing to use, but no intention to use PrEP, (4) PrEP aware, willing, and intending to seek PrEP within three months, and (5) current PrEP users.	Social identity support variable made form (1) gay community attachment, (2) sexual orientation disclosure, and (3) emotional support	Structural equation modeling, confirmatory factor analysis	There was a non-statistically significant direct result between social identity support and PrEP engagement (0.10 [− 0.12, 0.32]) There was an indirect but statistically significant association between social identity support and PrEP engagement (0.18 [0.09, 0.28]), via PrEP use in network
Burns, 2021 [43]	PrEP use in the last 12 months (yes/no)	Social support was measured using a previously validated four-item Emotional Support Scale, Cronbach α of 0.84. (Krause, 1995).	Univariate and bivariate analyses using SAS; multilevel logistic regressions	At the environmental level, there was a non-statistically significant result between social support cluster mean and PrEP use 0.78 (0.6, 1.01) At the individual level, there was a non-statistically significant results between social support and PrEP use 0.93 (0.81, 1.07)
Flores, 2020 [44]	Current PrEP use, PrEP use before sexual or drug use	Family Social Support was based on one item that asked participants to indicate the extent to which they received social/emotional support from their family (0 = Not at all, 1 = A little, 2 = Somewhat, 3 = A lot). Other items included comfort with parent-child sex communication, family disclosure of sexual orientation, family prioritization	Descriptive statistics, correlation tests to assess for multicollinearity, logistic regression	Family social support was not significantly associated with current PrEP use. However, comfort with parent sex communication was significantly associated with odds of current PrEP use in the final adjusted multivariable model (aOR = 1.87 (1.18–2.98, p = 0.008).
Harawa, 2020 [45]	PrEP awareness and use	Social support was an intervention component provided from social / educational group outings, and by a Peer Mentor pairing who provided support, encouragement, and navigation.	Descriptive statistics and either generalized linear mixed models with a logit link function or logistic regression, depending on the outcome variable	The Peer Mentor intervention arm had PrEP awareness and use increase from 0–22% compared to the control arm whose use increased from 0–9%. In logistic regression, the odds of current usage of PrEP was 0.39 (0.03–4.85) times as likely among Peer-Supported group compared to non-Peer-Supported (p-value 0.426).
Kelly, 2020 [46]	Currently taking PrEP (yes/no)	Social support was an intervention component provided in weekly group sessions plus two biweekly booster sessions. Sessions focused on inspiring / energizing network leaders to help friends avoid HIV infection by learning about PrEP, role-played conversations, learned about PrEP services, normalizing PrEP, and developing plans to assist friends in taking PrEP.	Multilevel models to assess PrEP over time. Included network as a fixed factor; linear, logistic, or negative binomial regression coefficients. ITT analysis.	From baseline to 3 months follow up, 3 participants initiated PrEP use between baseline and follow-up, increasing the percentage using PrEP from 3% (n = 1) to 11% (n = 4).
Meanley, 2021 [47]	Lifetime PrEP use ever (yes/no)	Gay community attachment was defined by four variables: “I feel that I am part of my area’s LGBTQ + community,” “Participating in my area’s LGBTQ + community is a positive thing for me,” “I feel a bond with the LGBTQ + community,” and “I am proud of my area’s LGBTQ + community”). Response options were on a 4-point scale (0 = Strongly disagree, 3 = Strongly agree), Cronbach’s α = 0.86.	Bivariate associations (chi-square, t-tests, Pearson’s correlation) and structural equation modeling, adjusting for age, race / ethnicity, sexual orientation, employment status, relationship status, and recent condomless intercourse.	Higher scores on gay community attachment were directly associated with lifetime PrEP use.
Quinn, 2020 [48]	Perceptions of PrEP and PrEP use among peers	Social and cultural factors (e.g., How would you describe the gay or LGBTQ + community in Milwaukee / Cleveland), friends, and peer groups (e.g., Thinking about your friendship circle or peer group, what percentage of them from 0 to 100 are gay / bisexual / transgender).	Team-based multi-stage analytic coding strategy to organize the data, create a codebook, refine the codebook, use axial coding to finalize the codebook, apply the codebook, and finally use thematic content analysis to identify themes.	The key themes were (1) how peers talk about PrEP, (2) filling gaps left by healthcare providers, (3) peers improved trustworthiness of PrEP, (4) reducing stigma and changing the narrative around PrEP, (5) a need for more leaders in the Black GBM community. Participants stated that friends, peers, and constructed or gay families were the primary source of PrEP information, which influenced how they viewed PrEP. Gossip, rumors, and stigma were barriers to PrEP, but openly discussing PrEP had the power to increase comfort and social change around PrEP. This filled knowledge gaps from their healthcare and medical providers. Participants also trusted their friends, peers, and constructed families more than healthcare providers, as the population has a lot of medical / pharmaceutical mistrust. Participants noted the need for identifying “movers and shakers”, leaders, or role models in the community.
Reback, 2019 [49]	Still on PrEP, number of missed doses in the past 4 days, number of missed doses in the past 30 days, and if they had not taken PrEP for 4 + days in a row.	A.S.K.-PrEP is a five-session peer navigator service program that took place over a 3-month period that was adapted from ARTAS (Antiretroviral Treatment Access Study), the CDC intervention for linkage to HIV care. The sessions consisted of a PrEP Knowledge Pre-test, assessing participant readiness for PrEP adherence, planning for adherence and removing any barriers to taking PrEP, and continue PrEP adherence. They also received adherence support text messages based on Social Support Theory, Health Belief Model, or Social Cognitive Theory.	Descriptive analysis	91.5% of MSM were successfully linked to PrEP care in a median number of 9 (IQR 4–15) days. 69.6% reported that they were still taking PrEP. 83.3% of MSM reported that they did not miss one PrEP dose in the previous 4 days, and 48.7% reported that they did not miss one PrEP dose in the previous 30 days. About 20% of participants (MSM: 19.2%) reported that they did not take a PrEP dose on four or more consecutive days in the previous 30 days. 46.5% of MSM elected to receive the adherence support text messages; these MSM were more likely to report that they still took PrEP medication than participants who did not receive the text messages (85.7% vs. 61.4%; χ2(1) = 12.0, p < 0.001). The association between text message support and PrEP adherence was significant for MSM (81.1% vs. 59.3%; FET, p = 0.014)
Rogers, 2022 [50]	Factors related to PrEP, costs associated with PrEP, pharmacy and mail order experiences, impact of COVID-19 on PrEP, thoughts on “next generation” PrEP, beliefs, and attitudes about PrEP as an HIV prevention / health promotion tool	Factors related to PrEP included social factors such as discrimination, their own experience with PrEP, and others’ experiences with PrEP	Deductively created a codebook, inductively coded emergent codes, themes, patterns, and conclusions	Participants reported that being active and supported in the LGBTQ + community normalized PrEP and therefore reduced the stigma associated with taking PrEP and provided support to engage and adhere to a PrEP regimen. They also felt that any person who was supportive in friendship or romantic relationships was an important factor for participants to stay on PrEP. Participants also reported that having access to medical providers who affirmed their sexual orientations and were knowledgeable about PrEP made them feel comfortable to ask questions about PrEP and improve their healthcare experience.
Ware, 2021 [51]	Adherence measured using DBS TFVdp	One of the three arms of this RTC was a bidirectional Facebook group	Descriptive analysis	Protective PrEP adherence DBS TFVdp levels were measured in 46% of the Financial Incentive group, 57% of the Social Media group, and 67% of the Control group (p = 0.38). Both the financial and social media arms had no statistical impact on PrEP adherence compared to the control arm.
Zapata, 2022 [52]	Time on PrEP	Interviews inquired about level of social support, social support involvement in care, social and PrEP-related stigma, and sharing their PrEP use with people in their life.	Guided by Grounded Theory, researchers took notes on all interviews, grouped concepts into categories, coded interviews using the category list, then refined thematic categories using comparative analysis.	Main themes included PrEP related stigma, relationship-related stigma, social support within the LGBTQ + community, psychological impact of PrEP, and access to care because of stigma. PrEP related stigma: Participants said that people in their networks often see PrEP as a gateway to have unprotected anal sex and have multiple partners. Some said this led them to hide their PrEP use. Some said this led them to attempt to increase empowerment around PrEP users. Relationship-related stigma: Participants felt that revealing they were on PrEP led others to judge their non-monogamous relationship status or felt conflict in a relationship for choosing to stay on PrEP. Social support within the LGBTQ + community: Many participants learned about PrEP from other queer men, leading them to seek out care from LGBTQ+-friendly medical providers so they would not feel judged or lectured. Establishing a well-known care network was critical. However, some participants reported encountering medical providers who did not know about PrEP and identified that as a significant barrier. Lack of communication with a provider in general felt judgmental or discriminatory. Discussing PrEP with other LGBTQ + men normalized PrEP use and made participants feel like a resource to their community, and provided and received companionship, informational support, and emotional support from their peers.

aOR, adjusted odds ratio; GBM, gay and bisexual men; CDC, Centers for Disease Control and Prevention; MSM, men who have sex with men; FET, Fisher’s exact test; DBS TFVdp, dried blood spot Tenofovir diphosphate