Introduction

HIV testing is vital for HIV prevention as it is the crucial point for the care continuum and declined transmission, critical to achieving the 95–95-95 targets of testing and treatment among people living with HIV by 2025 [1, 2]. However, the coverage of HIV testing in many settings is still low and needs to be improved. UNAIDS estimated that, in 2022, approximately 15% of people with HIV globally were unaware of their health status. About 50% of gay, bisexual, and other men who have sex with men (MSM) are estimated to be unaware of their infection in 2023. Key populations experienced a disproportionate burden from the HIV pandemic [3,4,5].

One method with the potential to enhance the coverage of HIV testing involves the utilization of social network approaches. These approaches are designed to activate social relationships or connections within key populations, including their networks of peers, friends, and sexual contacts [6, 7]. Previous studies indicated that compared to conventional clinic-based and provider-led venues, peer-driven outreach has demonstrated efficacy in reaching marginalized, under-represented, and concealed populations, and individuals with undiagnosed infections [8]. The interventions carried out by community peer leaders also yielded low levels of stigma and had notable impacts on disseminating HIV-related information and augmenting HIV testing behaviors among MSM [9]. Furthermore, peer-based distribution of HIV self-testing kits or partner testing through social networks proved an effective way to increase testing coverage among key populations [10••]. Thus, social network approaches have been adopted by the WHO and US CDC as an effective strategy for improving HIV testing coverage, especially among key populations [11].

Digital strategies or digital health were defined as web 2.0 internet-based applications embedded in health interventions or health services, such as websites, smartphone apps, short message service (SMS) text messages, etc. Digital strategies have been widely used in sexual health services promotion with high feasibility and acceptability [12, 13], moreover, these strategies gained profound strength in maintaining and expanding social networks among key populations. For example, geographical-based mobile apps or websites could break virtual boundaries and facilitate social relationship construction [14, 15]. Equipped with instant communication technologies, online digital platforms easily surmount geographical and temporal constraints, demonstrating the ability to reach and gather target individuals and their networks. Integrating digital strategies with social network approaches has the potential to improve the effectiveness of these two strategies.

As digital strategies were increasingly implemented, several review studies have recapped the impacts on HIV testing by developing STI/HIV testing services [12], integrating gamification, tailoring and delivering motivational and interventional messages [16], and prototyping digital platforms [17]. However, the capacity to combine digital strategies, social networks, and HIV testing remained under-summarized. Thus, in this review, we aimed to examine how digital strategies could practically enhance HIV testing, specifically through the social network approaches grounded in the existing evidence.

Methods

Following the five steps of Arksey and O'Malley's' framework [18], we conducted a scoping review to reveal the abovementioned research questions. This model contained 1) identification of a research question, 2) identification of relevant articles, 3) article selection, 4) data charting, and 5) collating, summarizing, and reporting the results. This method could map the studies effectively to examine emerging evidence in a distinctive research area [19].

Searching Strategies

To summarize how HIV testing promotion using social network approaches is supported by digital strategies, our search encompasses studies published from 1947 to June 2023 on Embase and from 1996 to June 2023 on PubMed. Based on the existing relevant research [12, 20, 21], we combined the following search terms: "HIV Infection"; "HIV Testing"; "Diagnosis"; "Screen"; "Telecommunications"; "Internet"; "Web-based"; "Technology"; "M-Health"; "Social Networking"; "peer network" to optimize the accuracy of the selection process in the databases—the detailed search terms are listed in Supplementary Table 1.

Selection Criteria

The data extraction process was conducted using Covidence. Two authors (Z.Y. and W.C.) independently reviewed the studies to ascertain the eligibility of the research for the current study objectives and devised the data extraction criteria. When encountering uncertainty in determination, three authors (Z.Y., Y.D., and W. T.) processed the co-full-text review, deliberated on eligibility, and reached a consensus. To highlight the implementation value of the evidence, we inspected and included studies if their study designs or implementation mentioned 1) the use of social networks or social relationships to promote HIV testing, 2) the description or measurements of the HIV testing-related outcomes, and 3) the utilization of digital techniques. Review articles, study protocols, commentary, conference abstracts, and non-English publications were excluded.

Data Extraction

We categorize the promotion of HIV testing into HIV testing uptake, HIV testing services distribution, HIV testing results, and HIV testing experience, and integrate with the dimensions of knowledge, attitude, and practice according to the included studies' results and aims. Then, the social network approach was divided according to the types and the closeness of the relationship triggered within the process of HIV testing promotion (such as peers, friends, sexual partners, etc.). The names of the platforms or services were initially used to identify the digital strategies. Then, they were sequentially merged into the technology type based on their supporting functions to the research (such as social media, information channels, etc.).

Result

The initial search yielded 1010 research articles up to June 2023 after removing 39 duplicates. Nine hundred seventeen studies were excluded after the title and abstract screening, and 64 were further excluded after full-text screening. The main reasons for exclusion were the absence of HIV testing results, ineligible study types (i.e., study protocols or commentary, etc.), and a lack of key components of digital strategies or social networks. Consequently, 29 eligible studies were included in this review (Fig. 1).

Overview

Of the included studies, all of them were conducted in the last ten years (from 2013 to 2023), and over half of the research was published after 2020 (58.6%, 17/29) [6, 10••, 22,23,24, 25••, 26••, 27,28,29,30,31,32,33,34,35,36]. Among the enrolled studies, the vast majority (96.6%, 28/29) included MSM as their study population [6, 8, 10••, 22,23,24,25••,26••, 28,29,30,31,32,33,34,35,36,37,38,39•, 40, 41, 42•, 43,44,45,46,47]. Other included studies also involved other sexual minority groups, such as transgender women (TGW) [37, 46], and female sex workers (FSW) [37, 38]. Only one study focused on male mountain porters and female bar workers as populations at high risk for HIV infection [27]. As for the study settings, 44.8% (13/29) of the studies were conducted in the US [6, 8, 22, 26••, 29, 35,36,37, 39•, 43, 44, 46, 47], followed by Asian countries such as China (34.5%, 10/29) [10••, 23, 24, 25••, 30,31,32,33,34, 40] and India (3.4%, 1/29)[42]. Only three studies were implemented in African countries [27, 28, 38], and another two studies in South America (Peru) [41, 45]. Regarding the study design, more than one-third (34.5%, 10/29) of the included research was cross-sectional studies [8, 10••, 22, 24, 27, 30, 32, 36, 37, 47], followed by eight (27.6% 8/29) randomized controlled trials [6, 25••, 26••, 35, 43,44,45,46], four (13.8%, 4/29) longitudinal studies [23, 39•, 41, 42] and three (10.3%,3/29) quasi-experimental studies[29, 33, 40]. One (3.4%,1/29) non-randomized control trial [28], one (3.4%, 1/29) retrospective cohort study [31], one (3.4%, 1/29) national pragmatic trial [34] and one (3.4%, 1/29) case study [38] measuring HIV self-testing distribution were also selected for review (Table 1).

Table 1 Overview of eligible studies
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HIV Testing

The included studies demonstrated two main types of social network-based interventions supported by digital strategies: the first is HIV health intervention, which promotes HIV testing through online HIV-related discussion and information dissemination within social networks; the second is HIV testing services distribution, which promotes HIV testing by directly distributing HIV testing kits or services through social networks. The aims of the studies include comparing the effectiveness of different modes (primarily between the digitally supported social-network-based intervention and non or standard of care), assessing the feasibility and acceptability of innovative testing promotion approaches, and cost-effectiveness studies.

Four primary HIV testing outcomes included: 1) HIV testing uptake and cognitive determinants (86.2%, 25/29), 2) HIV testing services distribution and cognitive determinants (51.7%, 15/29), 3) HIV testing results (62.1%, 18/29), and 4) HIV testing experience (6/29, 20.7%). The first outcome refers to the examination of whether HIV testing or HIV self-testing was performed among the participants, as well as the impact on the intention and efficacy of requesting or taking an HIV (self) test [8, 10••, 22, 24, 25••, 26••, 27,28,29,30,31,32,33,34,35,36,37,38,39•, 40, 42•, 43,44,45,46]. Studies focused on HIV testing distribution mainly investigated the behavior of distributing HIV testing kits or testing online request links to people in their social network, and the willingness to distribute, notify, and be notified of of available HIV testing services or the online request link for HIV testing service/testing kits [6, 8, 23, 24, 25••, 27, 30,31,32,33, 35,36,37, 39•, 47]. Most of the studies described the results of HIV testing, including test positivity and the proportions of new testers among the study population [6, 8, 10••, 22, 24, 25••, 27,28,29,30,31, 33,34,35, 38, 39•, 42•, 46]. In contrast, a few studies focused on detailed HIV testing experiences, such as the content and frequencies of HIV testing discussions during the intervention period or the testing preferences among the participants [22,23,24, 33, 41, 43].

Social Networks

Among the social network approaches, three forms of social network primarily used for HIV testing promotion were found. The first type of social network is that of LGBT community members [10••, 23, 24, 25••, 26••, 28, 29, 31,32,33,34,35, 37, 38, 40, 41, 42•, 43,44,45,46] who were connected on public platforms without any face-to-face connections. The second type is interpersonal social connections among the study population, such as sex partners [8, 10••, 23, 25••, 32, 36, 39•, 47], family members [8, 10••, 23, 27, 35, 47], friends [8, 10••, 23, 25••, 27, 32, 35, 39•, 47], and loved ones [27]. The third network type was based on social roles, such as coworkers [27] and neighbors [27]. Among those studies, eight of them integrated more than one type of social network into the study design [8, 10••, 23, 24, 25••, 27, 33, 35]. These studies predominantly triggered both community and interpersonal social connections of the participants to distribute HIV testing kits or health services.

Digital Strategies

Regarding digital support, most studies (96.6%, 28/29) adopted social media-based digital strategies [6, 8, 10••, 22,23,24,25••, 26••, 28,29,30,31,32,33,34,35,36,37,38,39•, 40, 41, 42•, 43,44,45,46,47], including general social media platforms (e.g., WhatsApp, Facebook, Line, WeChat, Internet chat rooms, etc.) [6, 8, 10••, 23, 24, 25••, 26••, 28, 30,31,32,33,34, 36,37,38,39•, 40, 41, 42•, 43,44,45], sexual minority-oriented apps (e.g., Grindr, Hornet, Jack'd, PlanetRomeo, A4A Radar, Scruff, etc.) [24, 28, 33, 36, 37, 42•, 46], online forums or social networking sites (e.g., Craigslist, etc.) [6, 22, 24, 26••, 35, 41, 44, 45], and websites for people living with or affected by HIV (e.g., POZ) [39•]. Some studies mentioned neither the name nor the category of the social platform [8, 29, 47]. In addition, various digital strategies such as SMS [27, 38], public websites [33], self-developed websites [29], web-based training [24], email [38], search engine [40], HIVST-specific apps [22] or app-based mini-program [25••] served as main [27] or supportive [22, 25••, 29, 33, 38, 40] tools to strengthen social network approach to HIV testing. According to the digital-based communication or interaction patterns in supporting social network approaches to HIV testing, we sorted the digital strategies into three main categories: social media platforms and applications, online information channels, and self-developed multifunctional digital platforms (See Fig. 2).

Social Media Platforms and Applications:

Social media-based strategies have been widely adopted to expand HIV testing among key populations, facilitating reaching and recruiting the target population and enabling communal interactions and exchange of HIV-related information among users, their social networks, and health workers [6, 8, 10••, 22,23,24,25••, 26••, 28,29,30,31,32,33,34,35,36,37,38,39•, 40, 41, 42•, 43,44,45,46,47]

Online Approach Facilitates Reaching and Recruiting the Target Population

Social media facilitated recruitment processes among key populations. Digital approaches such as banner ads on Facebook, online forums, or other social networking sites, and distinctive channels that consider regional and target users' preferences, yield significant strength in reaching uncovered participants.

In the included studies, three types of participants were recruited via the abovementioned channels. First, "peer leaders" [24, 33, 36, 42•] who mobilized or assisted others' participation in HIV testing. For example, the peer mobilization project named Mulakat in Mumbai [42•] used PlanetRomeo (the local MSM preferred social media site) to reach 5530 men and successfully recruit 247 participants, including 22 first-wave peer mobilizers. Those peer mobilizers provided coupons with unique codes to their social network to facilitate clinic-based HIV testing and reached 99% of first-time testers. Second, "index participants" [6, 8, 10••, 22, 23, 25••, 31, 32, 35, 39•, 47] were defined as those who directly distributed or were supposed to distribute the testing kits or testing request links within their networks, such as friends, sex partners, or community members. The online WeChat platform run by minority community-based organizations was used for reaching potential test distributors in several Chinese studies [10••, 23, 25••, 31, 32, 34].

In New York, a study recruited 48 cisgender men and transgender women who have sex with men by the combination of geospatial sexual networking applications, online forums, and offline centers, to screen their sexual partners using a smartphone-based HIV/syphilis test. Third, "intervention receivers" [22, 24, 26••, 27, 30,31,32,33, 36,37,38, 40, 42•, 45, 46] received or were supposed to receive the social network-based intervention, e.g. HIV testing/prevention-related messages, notifications, or invitations, from "peer leaders" or directly from program staff, or testing request links/testing kits from "index participants." In the series of HOPE projects, 900 African-American and Latino MSM in Los Angeles and 556 MSM in Peru were recruited through targeted banner ads on social networking sites (i.e., Facebook, Craigslist, and commonly used Peruvian gay websites) to receive peer leaders' information about HIV prevention and testing as the intervention [26••, 44, 45].

Social media outreach is an effective way to reach target populations. First, it gains high acceptability and efficiency in reaching populations at high risk for HIV. Of note, MSM from Mumbai extended a significant preference by recruiting from sexual minority-oriented apps [42•]. Moreover, compared to the traditional voluntary counseling and testing (VCT) model, social media outreach is more likely to precisely reach MSM who have the risk for HIV infection due to multiple sex partners, condomless sex, or substance use, or who do not test regularly [33]. Second, the cost of social media outreach is relatively low. WeChat-recruited sexual health influencers can encourage numerous alters to get self-tests [31]; thus, the average cost per person tested stimulated by social media key opinion leader index was relatively lower than in community-based organization (CBO) venues [34]. In contrast, social media outreach can lack the capacity to reach diverse participants such as older MSM[28].

Communicative Functions Support Health Information Delivery

Social media platforms with instant communication functions [6, 8, 10••, 22,23,24,25••, 26••, 28,29,30,31,32,33,34,35,36,37,38,39•, 40, 41, 42•, 43,44,45,46,47] allow online posting and facilitate the sharing and exchanging of online information, including recruitment messages, testing-related information, and links for HIV testing requests or appointments.

First, social media worked as a tool to reach or gather MSM community members for engagement in social network-based interventions. In some studies, "opinion leaders" were recruited to build [40] and/or operate [34, 40] public platforms on Facebook or WeChat to reach populations at high risk for HIV among social media users with HIV testing content. In other studies, existing [28, 46] or newly created [26••, 28, 41, 42•, 44] communication groups served as online communities to accommodate participants These online spaces such as gay dating apps or minority-friendly websites originally were designed for the key populations that fulfilled their daily needs, and were used for social-network-based HIV testing. Among those, privacy settings such as non-public groups [26••, 28, 41, 44] (i.e., unable to be accessed or searched for by nongroup members) and concealment of group members' contact details [42•] were adopted to protect identifiable information of the participants. Second, program staff offered pre-testing [30, 33, 37, 38, 42•] and post-testing [32, 42•] discussions or counseling via social media. In studies where pre-testing communications were conducted, participants were provided with HIV prevention education [33, 37, 42•], information about available HIV testing services [33, 37, 38], encouragement to refer their peers [33, 38], assistance in making testing appointments [30], and easing of fears about testing[38]. On the other hand, post-testing communications mainly focused on follow-up services such as HIV prevention messaging [42•], test results interpretation, and linkage to clinical confirmatory testing and treatment [32].

Communication and education about HIV testing services through social media exhibited high acceptance for both intervention receivers and peer leaders. For the intervention receivers, one study in the US revealed that over three-fifths of participants believed that a gay dating app is a proper channel to receive HIV information from peer navigators [37], and most of the participants were willing to notify sex partners through geospatial sexual networking apps (eg, Grindr, Scruff, Tinder) and be notified to get counseling and testing [36]. Regarding online group discussions, a study from Young [44] showed participants who were randomly assigned to closed Facebook groups with peer leaders who discussed HIV prevention and testing had higher acceptance and engagement in the social networking community compared to peer leaders who discussed general health topics in the closed Facebook groups. For the peer leaders, a pre-and post-comparison study demonstrated that educational training on HIV-related epidemiology, stigma, and the use of Facebook significantly increased the willingness and knowledge of peer leaders to engage in online HIV prevention interventions [41]. After receiving online opinion leaders' intervention, participants were more likely to access HIV-related information online and discuss HIV-related topics with their friends [40]. Their willingness and behaviors to perform HIV testing or self-testing were significantly increased [26••, 35, 36, 45].

Online Information Channels:

Several online information channels were used to assist in implementing social network-based HIV testing interventions [27, 33, 38, 40]. Although these strategies did not directly exaggerate participants’ social networks, they still showed connections with online or offline communities and promoted HIV testing among the key populations. Unlike general social media, these channels often support one-way online searching or messaging with limited user interactions. Likewise, these channels are grouped into three categories based on their functions:

Online Community Searching and Targeting:

Web-based search engines were used to identify online communities with high risk for HIV acquisition where social network approaches to promote HIV testing could be implemented. According to research conducted in Taiwan and China [40], standard search engines (i.e., Google, Yahoo, and Ping) were applied to identify the online virtual MSM community by using keyword searching methods (i.e., gay, AIDS, HIV, and other relevant search terms of interest.). After locating the online community, peer leaders were recruited from selected online communities to assist with participant recruitment for HIV testing. Then the selected peer leaders would conduct a 5-month intervention in those platforms identified by the search engine (such as Facebook) to promote the HIV testing performances of the participants [40].

Online Information Publicizing for Recruitment:

Aside from general social media, public websites could also support online recruitment. A study in Taiwan and China compared the HIV test positivity and confirmed diagnosis rates between participants recruited by the public website of a municipal hospital (control group) and participants recruited by social media (intervention group) [33].

Details of the upcoming testing for control group participants were posted daily on the public website of a municipal hospital, whereas designated HIV testing services were posted and could be booked for intervention group participants on social networking apps Results revealed that the HIV-positive and referral rates for confirmation diagnosis from the public website-based recruitment group (control group) were significantly lower than the social media-based group (intervention group) [33]. The public website-based control group was also less likely to reach people engaged in behaviors associated with HIV acquisition, including seeking sexual activity through social media, having multiple sexual partners and condomless anal intercourse, or using recreational drugs, and those who do not regularly test for HIV or have never tested, compared with the traditional model social media-based intervention group [33].

A self-developed website was also applied for recruitment in a U.S. study [29]. In the intervention arm, potential participants were directed to the recruitment website after clicking online advertisements on the asocial networking platform [29]. A series of questions on the website were then presented to screen participants for eligibility [29]. The website then showed detailed information on HIV testing services to eligible participants' websites [29]. This recruitment approach presents equal effects on diagnosed newly identified HIV infections compared to the county's directly funded programs [29].

One-way Messaging for Recruitment:

SMS [27, 38] and emails [38] were used to recruit participants for HIV testing by a one-way information dissemination [38]. Among the two studies in Africa [27, 38], text messaging services were used alone [27] or together with social media [27] for participant recruitment. Emails [38] were utilized through a similar process. In a study conducted in the Democratic Republic of Congo emails and SMS, together with social media, were used to disseminate messages about upcoming testing services to MSM and FSW communities [38]. Another study in Tanzania solely used SMS to send mobile phone-based testing invitations to social and sexual network contacts of male mountain porters and female bar workers testing for HIV [27]. The study conducted in Congo showed the feasibility of reaching MSM and FSW through a combined notification strategy of SMS, email, and Facebook by reporting the number of people tested and the percentage who tested HIV-positive [38]. As for the cross-sectional study in Tanzania, the feasibility and acceptability of implementing the novel mobile intervention were measured by the proportion of participants willing to test for HIV and distribute the SMS-based confidential social network referrals for HIV testing.

Self-developed Multifunctional Digital Platforms

The self-developed digital multifunctional platform is a hybrid strategy that provides supportive functions for achieving HIV testing or kit distribution. These types of packages include mini-programs embedded in existing social media [10••, 25••], web-based platforms[24], or mobile apps [22] designed by the research teams for social network-based HIV testing interventions specifically. Two categories of self-developed digital packages were identified:

Mini Program Assisting Testing Applying and referral to social networks

Studies conducted in China demonstrated the usage of a self-developed mini-program based on the WeChat platform initiated by local community-based organizations [25••]. Mini-program is one type of single mobile native application with advanced features for the users built within the WeChat platform. This type of technology was achieved by releasing the privilege to third-party companies. This program contained two main advantages including instant loading and ease of use [48]. Embedded in WeChat, this mini-program was multifunctional and designed for the cascade of social network distribution of HIV self-test kits, including approaches to applying HIV self-testing kits online, paying refundable deposits, mailing testing kits, and uploading test results. Index participants were recruited to distribute HIV or dual HIV/syphilis self-testing kits to their friends (straight and gay friends), sexual partners, and family members. The distribution could be performed through direct HIV testing kit sharing in person or by forwarding the virtual link or code connected to the mini-program online [10••, 24]. Then, the "alters" (who received the distribution) could upload photos of their test results anonymously and privately to the online mini-program [25••] followed by a monetary incentive, which simplifies the process of social network distribution of HIV self-test kits (for the detailed process see Fig. 3). The high return rate of 99% (1141/1150) [10] and the high proportion of new testers (about 34% to 40%) among the alters present high effectiveness and acceptability of expanding HIV self-testing among MSM [10••, 25••]. Moreover, combined with online peer referral links, participants were more likely to motivate more unique alters to get self-tested [25••].

Fig. 1
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Flowchart of the data extraction

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Fig. 2
figure 2

The forms of digital strategies, social networks, and HIV testing promotion and their relationships Note: the arrow symbols refer to how digital strategies enhance the social networks approach (the green arrow), how the social networks approach supports HIV testing (the yellow arrow), and how digital strategies assist HIV testing (the red arrow).

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Fig. 3
figure 3

The flow chart of how the developed mini program facilitates HIV testing expansion in the social network approach. Note: Bold Red showed how social networks were used in the process, and Bold Black showed how digital strategies were used in the process

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Self-developed Platform for Testing Guidance and Health Education

With consideration of the needs of the participant, some research utilized user-centered applications supporting HIV testing mentoring and interpretation. In such a practice in the US [22], the SMARTest app provided optional voiceover or video step-by-step instructions on HIV self-testing, which were reported to increase the knowledge of HIV testing and comfort, as well as partner HIV/STI testing. Moreover, the app also provided support after HIV testing, with a scanning feature that translated testing results into words to allow users to save or send results to others, and location-based resources and information for follow-up HIV care. Like the SMARTest, a web-based platform implemented in Hong Kong provided four pages of web-based training prior to the peer referral process to cultivate basic information on HIV, HIV self-tests, and study logistics for the index. Over 50% of participants who passed the training eventually successfully distributed at least one HIV testing kit [24]. These applications with supportive functions gained high acceptability by the participants, and over 70% of participants were willing to recommend the application to their social networks [22]. However, studies also revealed the challenges of using self-developed platforms. First, users with HIV testing experience and confidence may not value the supportive functions. Second, concerns about the privacy of HIV test results and lack of confidence to perform HIV self-testing using the test-supporting platforms. Specifically, inaccessible internet, software misuse, and hardware issues limit the full benefits of digital supportive tools [22].

Policy and Research Implications

Our scoping review indicates several important policy and research implications.

First, using digital strategies to implement social-network-based HIV testing is still partial and limited. The existing studies mainly highlight the advantages of digital support on social network strategies or HIV testing solely, and contribute to particular components such as 1) reaching and recruiting, which indicates the potential of information outreach on different types of social platforms; 2) gathering and identifying, which values the online target population community building and offline geographical tagging; 3) communicating and intervening, which underscores the online intervention delivery and message. However, there remains a lack of comprehensive strategies for utilizing digital approaches to facilitate all the abovementioned steps of the study implementation. Practices such as incorporating HIV testing peer-referral applications linking social media-based systems [10••, 25••], and studies are needed to examine the effectiveness and costs of hybrid strategies.

Second, the social-network-based HIV testing interventions supported by a digital strategy may yield effectiveness on HIV testing expansion[49], and it is crucial to adapt them to a broader population and distinctive social network types. The majority of current studies focused on the population aged around thirty [45], tend to exclude and marginalize aging MSM who may encounter difficulties in embracing digital strategies [28]. Additionally, inadequate studies focused on certain key and vulnerable populations in the HIV pandemic, such as adolescent girls, young transgender women, and others. Peer-driven strategies are profoundly prevalent in reaching and delivering health services to sex partners of the key populations [47]. Therefore, the HIV self-testing distribution from those people who acquired HIV could be highly effective in pinpointing key targets, which need more studies to explore. As some studies have observed, there is a phenomenon of distributing interventions through (straight) friend networks [10••]. So, amicable networks, such as heterosexual women friends of key populations, may demonstrate potential feasibility [50].

Thirdly, our scoping review indicates that we may integrate digital-supported social network HIV testing interventions with existing services to facilitate these strategies' use. Existing findings demonstrated a concentration of US and Asian studies, revealing a global imbalance in adopting these strategies. Based on our findings, those practices were mainly conducted on globally prominent media platforms, such as Facebook, or WhatsApp, which gained the feasibility to be adopted in a greater range, even in those digital-underdeveloped countries [51]. Additionally, incorporating community-based venues, identified as comparably effective in recruitment and peer education [34, 43, 44], could be integrated into practice. There is a need for policies and research endeavors that extend the application to these underrepresented study sites.

Conclusion

In summary, multiple digital strategies could support social-network-based intervention to expand HIV testing coverage among the key population. Consortiums of digital functions and under-estimated social relationships were needed to supplement the existing practice scope globally.