The Duration of Pharyngeal Gonorrhea: A Natural History Study

Pharyngeal gonorrhea is relatively common. However, the duration of untreated pharyngeal gonorrhea is unknown.

From March 2016 to December 2018, we enrolled 140 men who have sex with men 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 2 consecutive positive tests, and clearance as 2 consecutive negative tests; and, after visual inspection of the data, we reclassified up to 2 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. Finally, we report on the frequency of single-positive tests and the time between the last negative test and the positive test.

Nineteen (13.6%) of 140 participants experienced 21 pharyngeal infections (incidence, 31.7/100 person-years; 95% confidence interval, 20.7-48.6/100 person-years). The estimated median duration of pharyngeal gonorrhea was 16.3 weeks (95% confidence interval, 5.1-19.7 weeks). Twenty-two men had 25 single-positive specimens, a median of 7 days (interquartile range, 7-10 days) after their last negative test.

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.