Increasing prevalence of gonorrhoea and chlamydia among female sex workers in northern Sydney, 2005-2019

Background Recent reports indicate increasing gonorrhoea and chlamydia among female sex workers (FSWs) in Australia, with decreasing condom use for oral sex. Methods We determined trends in prevalence and positivity of gonorrhoea and chlamydia among FSWs attending our clinic from 2005 to 2019, by analysing data from medical and pathology records. We conducted a sensitivity analysis by using an alternative prevalence definition of first test result only per calendar year. Results Prevalence of gonorrhoea (all sites: pharynx, genital, rectal) increased from 1/130 (0.8%) in 2005 to 14/166 (8.4%) in 2012, to 31/257 (12.1%) in 2019; rate ratio (RR) 1.19, 95%CI 1.14-1.24, p(trend) < 0.001. There were rising trends for pharyngeal (RR 1.11, 95% CI 1.05-1.17, p(trend) = 0.001) and genital gonorrhoea (RR 1.17, 95% CI 1.08-1.26, p(trend) < 0.001). Prevalence of chlamydia (all sites) increased from 4/130 (3.1%) in 2005 to 8/166 (4.8%) in 2012, to 20/257 (7.8%) in 2019; RR 1.05, 95%CI 1.01-1.09, p(trend) = 0.006. This rise reflected predominately pharyngeal chlamydia (RR 1.16, 95%CI 1.04-1.29, p(trend) = 0.004). Qualitatively similar trends with similar significant results, were seen for gonococcal and chlamydial infections in the sensitivity analyses, indicating robustness of results to potential changes in testing frequency. Gonorrhoea and chlamydia were significantly associated with FSWs born in China. Chlamydia was significantly associated with age group 18-25. In the 2015-2019 period, of 89 women with gonococcal infections, 56 (62.9%) were pharyngeal-only; of 93 with chlamydial infections, 32 (34.4%) were pharyngeal-only infections. Conclusions FSWs require screening for pharyngeal as well as genital infections. Enhanced and sustainable health promotion is required.