LAUSR

Objectives Among men who have sex with men (MSM) in the UK,Chlamydia trachomatis (CT) and Neisseria gonorrhoea (NG) infections commonly occur asymptomatically at extragenital sites. Therefore, MSM seeking sexual health services are offered three-site (oropharyngeal, rectal and urogenital) STI screening. To increase access to screening, some UK sexual health services enable asymptomatic service users to order free STI screening kits online for self-sampling at home. We sought to assess prevalence of overall and extragenital CT/NG infection among asymptomatic MSM who used online self-testing in Hampshire, UK. Methods We assessed prevalence of CT/NG infections from non-pooled samples among asymptomatic cisgender MSM using an administrative database with results from 5601 STI screening kits returned between 20 December 2016 and 31 January 2020. We compared number of diagnoses of extragenital infection with urogenital results of the same individuals to determine prevalence of infection that would have been missed with urine testing alone. Results Among 5051 valid CT and 5040 valid NG asymptomatic test results, overall prevalence was 5.9% (298/5051) and 4.5% (228/5040), respectively. Among MSM with asymptomatic CT, 71.8% (214/298) had extragenital infection only, χ2 (1, n=298)=56.71, p<0.001. Among those with asymptomatic NG, 89.9% (205/228) had extragenital infection only, χ2 (1, n=228)=145.281, p<0.001. Conclusions Overall, most CT/NG infections among asymptomatic MSM who used online self-testing were extragenital. Given this and the likelihood of onward transmission from asymptomatic infection, it is recommended that three-site testing remain standard for MSM and free screening services be expanded in easily accessible ways.