The Duration of Pharyngeal Gonorrhea: A Natural History Study.

BACKGROUND Pharyngeal gonorrhea is relatively common. However, the duration of untreated pharyngeal gonorrhea is unknown. METHODS From March 2016 to December 2018, we enrolled 140 MSM in a 48-week cohort study. Participants self-collected pharyngeal specimens and completed a survey weekly. Specimens were tested using a nucleic acid amplification test at the conclusion of the study. We estimated the incidence and duration of infection. We defined incident infections as two consecutive positive tests, and clearance as two consecutive negative tests; and, after visual inspection of the data, we reclassified up to two weeks of missing or negative tests as positive if they occurred between 2 episodes of infections. We used Kaplan Meier estimates to define duration of infection. Lastly, we report on the frequency of single positive tests and the time between last negative test and the positive test. RESULTS Nineteen (13.6%) of 140 participants experienced 21 pharyngeal infections (incidence 31.7 per 100 person years (py); 95% CI 20.7 - 48.6 per 100 py). The estimated median duration of pharyngeal gonorrhea was 16.3 weeks (95%CI 5.1-19.7). Twenty-two men had 25 single positive specimens, a median of 7 days (IQR 7-10) following their last negative test. CONCLUSIONS The median duration of untreated pharyngeal gonorrhea is 16 weeks, more than double previous estimates. This long duration of infection likely contributes to high levels of gonorrhea transmission.