The efficacy and safety of preexposure prophylaxis (PrEP) for HIV prevention has been demonstrated through clinical trials among a range of at-risk populations, including men who have sex with men (MSM), people who inject drugs, and other high-risk populations [1-3]. The biomedical approach of daily oral antiretroviral medication is highly effective for preventing HIV when taken as prescribed [4,5]. To better facilitate the scale-up of PrEP and measure implementation progress, researchers proposed the PrEP care continuum (or PrEP care cascade, hereafter referred to as the PrEP continuum). Kelley et al [6] proposed a PrEP continuum framework to achieve protection for MSM that includes the following components: (1) at-risk MSM, (2) an awareness of and willingness to take PrEP, (3) access to health care, (4) a prescription for PrEP, and (5) adherence to effective PrEP. Nunn et al [7] expanded this framework as follows and included the additional step of retaining patients in PrEP care: (1) identifying individuals at highest risk for contracting HIV, (2) increasing HIV risk awareness among those individuals, (3) enhancing PrEP awareness, (4) facilitating PrEP access, (5) linking to PrEP care, (6) prescribing PrEP, (7) initiating PrEP, (8) adhering to PrEP, and (9) retaining individuals in PrEP care. Each step of the continuum represents a critical point for interventions, which can substantially increase the overall PrEP effectiveness at a population level. These frameworks guide researchers and practitioners to measure PrEP outcomes, and there are increasing numbers of published studies using the PrEP continuum to design and evaluate interventions to promote PrEP implementation worldwide [8-10].

In the past decade, electronic health and mobile health technologies, collectively referred to as technology-based interventions (TBIs), have seen exponential growth in the field of health care and health promotion. Examples of TBIs include disseminating health information on popular social media platforms, monitoring sleep duration and quality on wearable devices, sending push notifications to patients’ devices to support medication adherence, and using web-based chatrooms and meeting platforms for remote counseling [11]. These TBIs have several key features and functions that provide them with advantages over traditional health promotion interventions and programs, including their ability to reach a broader range of communities and individuals across diverse contexts, provide consistent services without the limitation of physical distance, and potentially be cost-effective and widely scalable once developed and adapted. Previous evaluation studies and meta-analyses have demonstrated and verified the effectiveness of such TBIs for supporting health behavior changes and disease management in several cases, including cardiovascular disease [12], diabetes [13], medication adherence [14], mental health, physical health [15], and sexual health including HIV and sexually transmitted infection prevention and care [16].

Compared to traditional HIV prevention interventions, TBIs can facilitate large-scale information dissemination and can effectively deliver just-in-time services and feedback to at-risk populations including MSM and people who inject drugs [17-19]. A recently published systematic review of TBIs related to HIV prevention and care cataloged published studies and other funded projects between 2014 and 2018 and found that there was a growing trend of TBIs and funded studies targeting various points on the HIV prevention and care continua with a substantial emphasis on education and behavior changes; however, there were no TBIs aiming to promote PrEP adherence and persistence [20]. From a nonsystematic review of various technologies used in HIV testing research, Romero et al [21] also noted that TBIs have the ability to increase outreach and HIV self-testing. To date, there is only one published review of TBIs involving PrEP; this review summarizes several telehealth programs aiming to improve PrEP availability, uptake, and adherence [22]. However, this review had some limitations. First, it is not clear whether it followed a systematic review guideline, and the authors only focused on telehealth approaches. Therefore, the results may not apply to all TBIs involving PrEP. In addition, similar to Maloney’s review [20], their analyses did not summarize the efficacy of each intervention and specifically evaluate which features of the interventions influenced each step of the PrEP continuum [22]. Finally, there was a lack of summary and evaluation on whether the TBIs were designed with guidance from a theoretical framework. In addition, little is known about the acceptability of and user experience associated with these TBIs and whether the interventions were scaled up and used in the real world after the completion of the study.

These considerations suggest the need for a comprehensive and rigorous review of the state of the science regarding TBIs and PrEP implementation. Therefore, the objectives of this systematic review are to (1) describe the use of TBIs in promoting steps along the PrEP continuum by population studied, (2) summarize the theoretical frameworks that have been used to inform and design the interventions, (3) summarize the evidence on and effectiveness of promoting steps along the PrEP continuum using the interventions, and (4) describe the acceptability of the TBIs among users, user experiences, and the sustainability of the intervention after study completion.

As of August 2021, we have completed the preliminary searches on the databases previously listed. A total of 1213 records were identified. Eligibility screening and data extraction are ongoing. It is anticipated that the final review will be completed and submitted for publication in summer 2022.

The emergence of TBIs in public health research has created opportunities for health promotion and disease prevention. A growing number of intervention studies have investigated the effect of TBIs in supporting the PrEP continuum among various at-risk populations. This systematic review will provide an overview of these TBIs and describe the evidence supporting their use and their efficacy. The review will highlight which kind of interventions have been implemented and which PrEP continuum step(s) are primarily targeted. Furthermore, this review will be the first to summarize the theoretical frameworks used for informing TBI design. The findings of this review will summarize successful experiences and lessons learned from published literature, conference abstracts, NIH RePORT, and unpublished data. The findings will also inform the design and implementation of future studies on PrEP care promotion.