Introduction There is increasing concern about Mycoplasma genitalium as a cause of urethritis, cervicitis, PID, infertility and ectopic pregnancy. Currently there is no licensed test specific for M. genitalium in the UK, where urethral smear microscopy is recommended in GUM clinics, for symptomatic men only. NAATs testing has been advocated, particularly to detect asymptomatic infection. However, M. genitalium’s natural history is poorly-understood, making the impact and cost-effectiveness of screening unclear.

Methods We used a transmission-dynamic model to synthesise evidence from epidemiological and behavioural studies, and surveillance data for Non-Chlamydial, Non-Gonococcal Urethritis (NCNGU), to better-understand the natural history of M. genitalium. The model is stratified by sex, and incorporates heterogeneous sexual behaviour, symptomatic and asymptomatic infection; PID; care-seeking due to symptoms and routine screening; and treatment failure. We fitted to national surveillance data, (allowing for uncertainty in studies measuring the amount of NCNGU caused by M. genitalium). We examined the effects of implementing NAAT testing for both sexes in GUM and GP settings.

Results Introducing NAAT testing for all men (asymptomatic and symptomatic, in GPs and GUM) detects much more infection in men and treatment reduces transmission to women, whilst testing of women reduces prevalence in women and incidence in men. Introducing NAAT testing for both sexes reduces cumulative PID incidence over 20 years by 13.1%(IQR:9.6%–18.3%). However, there is important uncertainty in M. genitalium’s natural history parameters, leading to uncertainty in the absolute reduction in PID and other sequelae. Particularly important are the proportion of infections that are symptomatic in men and women; duration of untreated infection; and incidence of PID, infertility and ectopic pregnancy attributable to M. genitalium.

Conclusion Further empirical work is required to improve understanding of the key aspects of M. genitalium’s natural history which we have identified before it will be possible to determine if screening is cost-effective.

Disclosure of interest statement This presentation reports independent research commissioned by the National Institute for Health Research (NIHR) under its Programme Grants for Applied Research scheme (RP-PG-0707–10208). In addition, PJW thanks the UK Medical Research Council for Centre funding (grant MR/K010174/1) and also thanks the UK National Institute for Health Research Health Protection Research Unit (NIHR HPRU) in Modelling Methodology at Imperial College London in partnership with Public Health England (PHE) for funding (grant HPRU-2012–10080). The views expressed in this paper are those of the authors and not necessarily those of the NHS, the NIHR, the Department of Health, or Public Health England. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. We have no conflicts of interest.