Archive for July 19, 2014

Syphilis Predicts HIV Incidence Among Men and Transgender Women Who Have Sex With Men in a Preexposure Prophylaxis Trial

Clin Infect Dis 2014 June 16 

Marc M. Solomon1,2, Kenneth H. Mayer4,5, David V. Glidden2, Albert Y. Liu3, Vanessa M. McMahan1, Juan V. Guanira6, Suwat Chariyalertsak7, Telmo Fernandez8, and Robert M. Grant1,2 for the iPrEx Study Teama

+ Author Affiliations

1The Gladstone Institutes

2University of California

3Bridge HIV, San Francisco Department of Public Health, California

4Fenway Health, Beth Israel Deaconess Medical Center, Fenway Institute

5Harvard Medical School, Boston, Massachusetts

6Investigaciones Medicas en Salud, Lima, Peru

7Research Institute for Health Sciences and Department of Community Medicine, Faculty of Medicine, Chiang Mai University, Thailand

8Fundacion Ecuatoriana Equidad, Guayaquil, Ecuador

Correspondence: Marc M. Solomon, MD, MPH, 1650 Owens St, 5th Floor, San Francisco, CA 94158 (

Syphilis infection may potentiate transmission of human immunodeficiency virus (HIV). We sought to determine the extent to which HIV acquisition was associated with syphilis infection within an HIV preexposure prophylaxis (PrEP) trial and whether emtricitabine/tenofovir (FTC/TDF) modified that association.


The Preexposure Prophylaxis Initiative (iPrEx) study randomly assigned 2499 HIV-seronegative men and transgender women who have sex with men (MSM) to receive oral daily FTC/TDF or placebo. Syphilis prevalence at screening and incidence during follow-up were measured. Hazard ratios for the effect of incident syphilis on HIV acquisition were calculated. The effect of FTC/TDF on incident syphilis and HIV acquisition was assessed.


Of 2499 individuals, 360 (14.4%) had a positive rapid plasma reagin test at screening; 333 (92.5%) had a positive confirmatory test, which did not differ between the arms (FTC/TDF vs placebo, P = .81). The overall syphilis incidence during the trial was 7.3 cases per 100 person-years. There was no difference in syphilis incidence between the study arms (7.8 cases per 100 person-years for FTC/TDF vs 6.8 cases per 100 person-years for placebo, P = .304). HIV incidence varied by incident syphilis (2.8 cases per 100 person-years for no syphilis vs 8.0 cases per 100 person-years for incident syphilis), reflecting a hazard ratio of 2.6 (95% confidence interval, 1.6–4.4; P < .001). There was no evidence for interaction between randomization to the FTC/TDF arm and incident syphilis on HIV incidence.


In HIV-seronegative MSM, syphilis infection was associated with HIV acquisition in this PrEP trial; a syphilis diagnosis should prompt providers to offer PrEP unless otherwise contraindicated.



July 19, 2014 at 10:26 am


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