Oropharyngeal Chlamydia trachomatis in women; Spontaneous clearance and cure after treatment (FemCure)

Objectives: Women attending STI clinics are not routinely tested for oropharyngeal Chlamydia trachomatis (CT) infections. We aimed to assess spontaneous clearance of oropharyngeal CT and cure after antibiotic treatment in women. Methods: Women with vaginal or rectal CT (n=560) were recruited at STI clinics in 2016-2017, as part of the FemCure study (prospective cohort study). We included participants' data from week -1, that is, the diagnosis at initial visit, when clinics applied selective oropharyngeal testing. At week -1, a total of 241 women were oropharyngeally tested (30 positive) and 319 were untested. All FemCure participants provided nurse-collected oropharyngeal samples at study enrolment, that is, week 0, just prior to treatment (n=560), and after treatment at weeks 4 (n=449), 8 (n=433) and 12 (n=427). Samples were tested by nucleic acid amplification test, and at week 0 also by viability testing by viability PCR. Proportions of oropharyngeal CT test results were presented to represent spontaneous clearance and cure. Results: Of 30 women diagnosed with oropharyngeal CT at week -1, fifteen (50%) were negative at week 0 after a median of 9 days, that is, € spontaneous clearance'. At week 0, a total of 560 participants were tested, and 46 (8.8%) were oropharyngeal CT positive; 12 of them (26.1%) had viable CT. Of the 46 positive, 36 women had an oropharyngeal test after treatment; 97.2% (35/36) were negative at week 4, that is, € cure'. Of all women with follow-up visits, the proportion of oropharyngeal CT positive was between 0.5% and 1.6% between weeks 4 and 12. Of those not tested at week -1 (n=319), 8.5% (n=27) were oropharyngeal positive at week 0. Conclusions: The clinical importance of oropharyngeal CT in women is debated. We demonstrated that spontaneous clearance of oropharyngeal CT among women is common; of those who did not clear for CT, three-quarters had non-viable CT. After regular treatment with azithromycin or doxycycline, cure rate (97%) of oropharyngeal CT is excellent. Trial registration number: NCT02694497