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HIV Prevention: Digital Health Interventions to Improve Adherence to HIV Pre-Exposure Prophylaxis


What the CPSTF Found

About The Systematic Review

The CPSTF finding is based on evidence from a systematic review of 7 studies (search period January 2000 to September 2021). Eligible studies were identified through a three-step process: CDC librarians identified eligible studies through a three-step process. First, they conducted searches and compiled a database of publications relevant to PrEP. Next, they performed queries within this database for publications relevant to digital health interventions to improve PrEP adherence. And finally, they conducted a PubMed search to identify more recent publications potentially relevant to PrEP.

The systematic review was conducted on behalf of the CPSTF by a team of specialists in systematic review methods, and in research, practice, and policy related to HIV prevention, treatment, and care.


Ending the HIV Epidemic in the United States External Web Site Icon is the operational plan developed by agencies across the U.S. Department of Health and Human Services (HHS) to pursue the goal of reducing new HIV infections by 75% by 2025 and 90% by 2030. HHS identified four key strategies to achieve these goals in the United States: diagnose people living with HIV as early as possible after infection, treat people with HIV rapidly and effectively to reach sustained viral suppression, prevent new HIV transmission through evidence-based interventions such as PrEP, and respond quickly to potential HIV outbreaks. The HIV National Strategic Plan (2021-2025) External Web Site Icon is closely aligned with, and complements, Ending the HIV Epidemic. This plan aims to integrate coordinated efforts that address the HIV epidemic among all partners and stakeholders, prevent new HIV infections, improve health outcomes of people with HIV, and reduce HIV-related disparities and health inequities.

The U.S. Preventive Services Task Force (USPSTF) recommends that clinicians offer PrEP to persons who are at higher risk of HIV acquisition (USPSTF 2019 External Web Site Icon). When taken daily as prescribed, PrEP reduces the risk of getting HIV from sex by 99% and from injection drug use by at least 74% (CDC HIV External Web Site Icon). There is a strong connection between adherence to PrEP and its effectiveness in preventing HIV acquisition; reduced adherence is associated with marked declines in effectiveness (USPSTF 2019 External Web Site Icon).

Summary of Results

Detailed results from the systematic review are available in the CPSTF Finding and Rationale Statement.

The systematic review included 7 studies.


  • Interventions increased “good adherence” to PrEP (defined as taking four or more doses of PrEP per week) by a median of 10.0 percentage points or a median of 11.1% when compared with standard care (5 studies).
  • Interventions increased “excellent adherence” to PrEP (defined as taking seven doses of PrEP per week) by a median of 20.0 percentage points or a median of 122.4% when compared with standard care (3 studies).
  • One study found adding visualized feedback to an app increased the number of participants achieving excellent adherence but did not reduce the number of participants with “poor adherence” (defined as less than four doses per week).
  • One study reported the intervention group missed fewer doses of PrEP when compared with the control group.


  • One study found the intervention improved retention in PrEP care, measured as the proportion of participants who attended all of their clinic visits.

Summary of Economic Evidence

A systematic review of economic evidence has not been conducted.


Based on results from the systematic review, the CPSTF finding should be applicable to younger gay and bisexual men and other men who have sex with men (collectively referred to as MSM) in urban U.S. settings independent of socioeconomic status, race, or ethnicity, or substance use.

Evidence Gaps

CPSTF identified several areas that have limited information. Additional research and evaluation could help answer the following questions and fill remaining gaps in the evidence base. (What are evidence gaps?)


  • How effective are digital health interventions for rural areas?

Population characteristics:

  • How effective are these interventions for the following populations?
    • Older adults
    • Females and transgender persons
    • People in racial or ethnic minority groups
    • People with mental health issues
    • People who engage in excessive alcohol use or drug use (including injection drug use)

Intervention characteristics:

  • Does intervention effectiveness change by offering participants the following?
    • All or part of the necessary equipment, such as mobile phones or data plans
    • Materials and communications in languages other than English
    • In-person services

Study Characteristics

  • Included studies were conducted in the United States (6 studies) and The Netherlands (1 study).
  • Studies evaluated a digital app only (2 studies), an app plus text messaging (1 study), text messaging only (1 study), or text messaging plus email, phone, or internet communication (3 studies).
  • Digital health services included medication reminders (5 studies), information and education (4 studies), adherence tracking (2 studies), support groups (2 studies), and counseling (1 study).
  • Interventions communicated with participants daily (2 studies), weekly (3 studies), or monthly (1 study).
  • Participants received feedback in one or more of the following ways: unidirectional communication (pre-set messages; 3 studies), automated bidirectional communication (questions were answered by pre-set messages; 3 studies), or personalized bidirectional communication (questions were answered by support person in real time; 2 studies).