Human Immunodeficiency Virus Pre-exposure Prophylaxis and Increased Incidence of Sexually Transmitted Infections in the United States.

Background: Human immunodeficiency virus (HIV) pre-exposure prophylaxis (PrEP) decreases HIV transmission. Some studies have raised concerns about a potential association between the implementation of HIV PrEP and the growing incidence rates of sexually transmitted infections (STIs) in the United States.
Methods: We conducted a quasi-experimental (interrupted time series) analysis of STI (syphilis, gonorrhea, and chlamydia) rates before (2000-2012) and after (2013-2017) the implementation of HIV PrEP. We also performed correlations between HIV PrEP utilization and STI cases at the national (2012-2017) and state (2017) levels. We defined HIV PrEP utilization as the number of people taking tenofovir disoproxil fumarate/emtricitabine for HIV prevention.
Results: HIV PrEP implementation was associated with 25% (relative risk [RR] 1.254, 95% confidence interval [CI] 1.245-1.263; P < .001) and 26% (RR 1.260, 95% CI 1.257-1.264; P < .001) increases in syphilis and gonorrhea rates, respectively, and a 12% reduction in chlamydia rates (RR: 0.884, 95% CI 0.883-0.885; P < .001). HIV PrEP utilization was correlated with the numbers of syphilis, gonorrhea, and chlamydia cases (spearman coefficients 1.00, 0.94, and 0.94, respectively; P < .001, P < .01, and P < .01, respectively). At the state level, HIV PrEP was also correlated with the number of cases of syphilis, gonorrhea, and chlamydia (spearman coefficients 0.85, 0.81, and 0.85, respectively; Ps < .001 for all correlations).
Conclusions: The implementation and utilization of HIV PrEP in the United States were associated with increased rates of STIs. Further studies to confirm these associations and to elucidate potential causes are needed.
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