Sexually Transmitted Infections

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Rates of sexually-transmitted infections (STIs) continue to increase within the Military Health System. Improved prevention and treatment approaches are critical to reduce the burden of STIs on Force Health Protection and medical readiness, as well as limit the contribution of deployed service members to the growing global dissemination of emerging and resistant STIs.

There is currently an epidemic of STIs in the United States, with sustained national increases in chlamydia, gonorrhea, and syphilis. What is notable is that the rates of  select bacterial STIs in military service members are regularly 2-3 times higher than those seen in civilian counterparts, demonstrating the impact of this national epidemic within the Department of Defense (DoD).                                                     

With the emergence of multidrug-resistant Neisseria gonorrhoeae (GC) and high levels of antimicrobial resistance of Mycoplasma genitalium, the STI Research Area aims to evaluate high-risk sexually-transmitted pathogens, support the development of biomedical countermeasures  against STIs in military populations, and evaluate novel treatment strategies and test prevention efforts among active-duty personnel to support policy decisions and improved practice patterns.

The GC Resistance Study (led by COL Eric Garges) and the DoD GC Reference Laboratory and Repository (coordinated by the IDCRP and led by Dr. Ann Jerse, USU) continue to be the backbone of the STI Research Area with >900 subjects enrolled. A concern for the Military Health System has been the acquisition of resistant GC during deployment; however, GC isolates collected within the health system have demonstrated similar levels of resistance to commonly used antibiotics compared to national data reported by the Centers for Disease Control and Prevention (CDC) Gonococcal Isolate Surveillance Project for the corresponding regions. Further identification of network clustering of GC isolates is underway in collaboration with informaticists at the Walter Reed Army Institute of Research (WRAIR) Multidrug-Resistant Organism Repository and Surveillance Network (MRSN), which may include classification of isolates from remote non-DoD networks.

Led by Dr. Anuradha Ganesan, the 3 Anatomic Site GC/CT Testing Among HIV+ and HIV- high-risk DoD Beneficiaries study aims to examine the prevalence of and risk factors for gonorrhea and chlamydia at multiple anatomic sites. Findings from this study have provided valuable information on the incidence of extragenital disease in high-risk groups within the Military Health System, as well as data on the antimicrobial resistance of GC. In addition, the study validated the value of self-collected verses provider-collected swabs for STI testing and demonstrated the viability of early-stream urine for culture of GC. Enrollment in the second phase of the study involving a high-risk HIV-negative population (DoD pre-exposure prophylaxis users) was completed in 2019.

During the past year, a new protocol was initiated to evaluate use of the OMV meningitis B vaccine (Bexsero®) for primary prevention of gonorrhea. Led by COL Garges, the study utilizes serum collected through the DoD Serum Repository from service members vaccinated with Bexsero® to study the host response to the vaccine and surrogate markers of protection against GC in vitro. Findings from this study will lay the groundwork for a clinical trial presently being developed to evaluate the efficacy of Bexsero® against gonorrhea (trial sponsored by National Institute of Allergy and Infectious Diseases (NIAID), Division of Microbiology and Infectious Diseases).

In the upcoming year, the GC Resistance Study protocol will be amended to allow for comprehensive surveillance of bacterial STIs other than GC, including genital mycoplasma and chlamydia. In addition, the modified GC Resistance Study will include the evaluation of antimicrobial resistance, infection persistence, and patient-derived clinical outcomes for these bacterial STIs, which will provide new opportunities for partnerships with academia.

Military Impact

The overall goal of the STI Research Area is to support the prevention, diagnosis, and treatment of STIs to eliminate STI transmission among active-duty members and beneficiaries and improve Force Health Protection. Findings from the GC Resistance Study provide valuable up-to-date information on the geographic distribution of isolates connected to antimicrobial susceptibility patterns, which are used for operational planning by the DoD. Susceptibility testing and advanced molecular characterization of isolates collected from within the United States and at overseas sites are assessed through the DoD GC Resistance Laboratory and Repository. Epidemiologic data on increasing resistance to azithromycin among GC isolates in the Western United States also continues to be provided to Combatant Commands through the Global Emerging Infections Surveillance (GEIS) Data to Decision Initiative for situational awareness and response, as needed. Furthermore, engagement with partner militaries for GC surveillance is active in Ghana, Thailand, Peru, and the Republic of Georgia, which provides not only valuable local Force Health Protection data, but also supports improvements in the technical capabilities and laboratory methods for our host nation partners.

Highlights / Key Findings

  • Among active-duty servicewomen in the U.S. Navy with endocervical chlamydia infections, there was a high rate of concurrent anorectal infections. The findings
    indicate a need for extragenital screening among high-risk patients, as well as increased education and behavioral interventions (use of condoms). This article was included in the evidence review for the revision of the U.S. Sexually-Transmitted Disease Treatment Guidelines at the CDC Treatment Guidelines 2019 meeting.
  • The value of the GC Resistance Study and the DoD GC Reference Laboratory and Repository was recognized as the DoD (represented by COL Garges) was invited to be a stakeholder and participate in a World Health Organization 2019 protocol planning meeting related to GC surveillance.
  • The Survey of Social Networks and STI Risk study completed enrollment (>700 subjects) and is the first time a dedicated sexual network risk study will address formation of sexual partnerships and risk of STIs among active-duty personnel.