Risk of sexually transmitted infections among U.S. military service members in the setting of HIV pre-exposure prophylaxis use

Jason M Blaylock; Evan C Ewers; Elizabeth J Bianchi; David B King; Rosemary O Casimier; Hector Erazo; Stephen Grieco; Jenny Lay; Sheila A Peel; Kayvon Modjarrad; Charmagne G Beckett; Jason F Okulicz; Paul T Scott; Shilpa Hakre

doi:10.1371/journal.pone.0296054

Risk of sexually transmitted infections among U.S. military service members in the setting of HIV pre-exposure prophylaxis use

PLoS One. 2023 Dec 28;18(12):e0296054. doi: 10.1371/journal.pone.0296054. eCollection 2023.

Authors

Jason M Blaylock¹, Evan C Ewers², Elizabeth J Bianchi^{3

4

5}, David B King³, Rosemary O Casimier^{3

4}, Hector Erazo^{3

4}, Stephen Grieco^{3

6}, Jenny Lay^{3

5

7}, Sheila A Peel⁸, Kayvon Modjarrad⁵, Charmagne G Beckett⁹, Jason F Okulicz¹⁰, Paul T Scott⁵, Shilpa Hakre^{3

4

5}

Affiliations

¹ Infectious Diseases Service, Walter Reed National Military Medical Center, Bethesda, Maryland, United States of America.
² Infectious Diseases Service, Fort Belvoir Community Hospital, Fort Belvoir, Virginia, United States of America.
³ Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, United States of America.
⁴ U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America.
⁵ Emerging Infectious Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America.
⁶ Level One Personnel, Columbia, Maryland, United States of America.
⁷ Preventive Medicine Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America.
⁸ Diagnostics and Countermeasures Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America.
⁹ Navy Bloodborne Infection Management Center, Bethesda, Maryland, United States of America.
¹⁰ Infectious Diseases Service, San Antonio Military Medical Center, Fort Sam Houston, Texas, United States of America.

Abstract

Background: The evidence for an increased incidence of sexually transmitted infections (STIs) among patients utilizing HIV pre-exposure prophylaxis (PrEP) has been inconsistent. We assessed the risk of incident STI while on PrEP compared to periods off PrEP among military service members starting PrEP.

Methods: Incidence rates of chlamydia, gonorrhea, syphilis, hepatitis C virus, and HIV were determined among military service members without HIV prescribed daily oral tenofovir disoproxil fumarate and emtricitabine for HIV PrEP from February 1, 2014 through June 10, 2016. Hazard ratios for incident STIs were calculated using an Anderson-Gill recurrent event proportional hazard regression model.

Results: Among 755 male service members, 477 (63%) were diagnosed with incident STIs (overall incidence 21.4 per 100 person-years). Male service members had a significantly lower risk of any STIs (adjusted hazard ratio (aHR) 0.21, 95% CI 0.11-0.40) while using PrEP compared to periods off PrEP after adjustment for socio-demographic characteristics, reasons for initiating PrEP, surveillance period prior to PrEP initiation, and the effect of PrEP on site and type of infection in multivariate analysis. However, when stratifying for anatomical site and type of infection, the risk of extragenital gonorrhea infection (pharyngeal NG: aHR 1.84, 95% CI 0.82-4.13, p = 0.30; rectal NG: aHR 1.23, 95% CI 0.60-2.51, p = 1.00) and extragenital CT infection (pharyngeal CT: aHR 2.30, 95% CI 0.46-11.46, p = 0.81; rectal CT: aHR 1.36, 95% CI 0.81-2.31, p = 0.66) was greater on PrEP compared to off PrEP although these values did not reach statistical significance.

Conclusions: The data suggest entry into PrEP care reduced the overall risk of STIs following adjustment for anatomical site of STI and treatment. Service members engaged in PrEP services also receive more STI prevention counseling, which might contribute to decreases in STI risk while on PrEP.

Copyright: This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.

MeSH terms

Gonorrhea* / epidemiology
Gonorrhea* / prevention & control
HIV Infections* / epidemiology
HIV Infections* / prevention & control
Homosexuality, Male
Humans
Male
Military Personnel*
Pre-Exposure Prophylaxis*
Sexual and Gender Minorities*
Sexually Transmitted Diseases* / epidemiology
Sexually Transmitted Diseases* / prevention & control

Grants and funding

This study was supported in part by the U.S. Army Medical Research and Development Command under Contract No W81XWH-16-C-0225 and by the Combined HIV and Infectious Disease Agreement (CHIDA) cooperative agreement (W81XWH-18-2-0040) between the Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc. (HJF), and the U.S. Department of Defense. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.