Projected Impact of Concurrently Available Long-Acting Injectable and Daily-Oral Human Immunodeficiency Virus Preexposure Prophylaxis: A Mathematical Model

J Infect Dis. 2021 Jan 4;223(1):72-82. doi: 10.1093/infdis/jiaa552.


Background: Long-acting injectable (LAI) human immunodeficiency virus (HIV) preexposure prophylaxis (PrEP) is reportedly efficacious, although full trial results have not been published. We used a dynamic network model of HIV transmission among men who have sex with men to assess the population impact of LAI-PrEP when available concurrently with daily-oral (DO) PrEP.

Methods: The reference model represents the current HIV epidemiology and DO-PrEP coverage (15% among those with behavioral indications for PrEP) among men who have sex with men in the southeastern United States. Primary analyses investigated varied PrEP uptake and proportion selecting LAI-PrEP. Secondary analyses evaluated uncertainty in pharmacokinetic efficacy and LAI-PrEP persistence relative to DO-PrEP.

Results: Compared with the reference scenario, if 50% chose LAI-PrEP, 4.3% (95% simulation interval, -7.3% to 14.5%) of infections would be averted over 10 years. The impact of LAI-PrEP is slightly greater than that of the DO-PrEP-only regimen, based on assumptions of higher adherence and partial protection after discontinuation. If the total PrEP initiation rate doubled, 17.1% (95% simulation interval, 6.7%-26.4%) of infections would be averted. The highest population-level impact occurred when LAI-PrEP uptake and persistence improved.

Conclusions: If LAI-PrEP replaces DO-PrEP, its availability will modestly improve the population impact. LAI-PrEP will make a more substantial impact if its availability drives higher total PrEP coverage, or if persistence is greater for LAI-PrEP.

Keywords: HIV; mathematical model; men who have sex with men; preexposure prophylaxis; sexual network.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Administration, Oral
  • Anti-HIV Agents / administration & dosage*
  • HIV Infections / epidemiology
  • HIV Infections / prevention & control*
  • HIV Infections / transmission
  • Humans
  • Incidence
  • Injections
  • Male
  • Medication Adherence / psychology
  • Medication Adherence / statistics & numerical data*
  • Models, Theoretical
  • Pre-Exposure Prophylaxis / methods*
  • Prevalence
  • Sexual and Gender Minorities / statistics & numerical data*


  • Anti-HIV Agents