Introduction
Worldwide each year, there are an estimated 357 million new infections of one of the four curable sexually transmitted infections (STIs): chlamydia, gonorrhoea, syphilis and trichomoniasis.1 2 Aetiological diagnosis via STI testing is the best way to ascertain infection status and promote appropriate treatment.3 4 While STI diagnostic tests are available and used in many high-income countries, diagnostic tests in low-income and middle-income country (LMIC) settings are largely unavailable.3 5–7 Syndromic management has been the primary approach for STI treatment in LMICs,5 8 which has significant limitations despite its practicality; experts doubt it will impact STI disease burden.5 9 10 Globally, social stigma and a lack of effective policies also affect STI testing uptake and treatment-seeking behaviour. Low STI testing coverage and high transmission rates are common among at-risk vulnerable adolescents and key populations including men who have sex with men (MSM), migrants, sex workers, Indigenous and minority populations and those affected by humanitarian emergencies.9 Left undiagnosed and untreated, curable STIs can cause acute and chronic illness, infertility, ectopic pregnancy, long-term disability, neurological and cardiovascular disease and death.11 Serious diseases in their own right, STIs also increase the risk of contracting or transmitting HIV infection.11 Consequently, greater efforts are needed to expand STI testing globally to reduce this heavy burden of disease.
Self-collection of samples is one way to facilitate the expansion of STI testing services. Self-collection of samples occurs when individuals take a specimen themselves, either at the clinic or elsewhere, and send it to a laboratory for testing.12 Follow-up in the case of positive test results requires a linkage with the health system. Research in high-income countries, where organised lab facilities and healthcare are available, shows that self-collected STI samples are as diagnostically accurate as clinician-collected samples13 and that self-collection interventions are feasible and acceptable in a variety of populations.14–23 Self-collection approaches also have the potential to address some common barriers to clinician-dependent and/or clinic-based diagnosis, such as concerns around autonomy, inconvenience, stigma and lack of privacy.5 24 25 Systematic reviews have been conducted to compare STI testing programmes (some including self-collection methods) in home or non-clinic settings to those in clinic settings.19 26–31 However, no review to date has systematically compared self-collection of samples to clinician-collected methods for STI testing on programmatic outcomes. In order to develop WHO guidance on self-care interventions for sexual and reproductive health and rights, we conducted a systematic review to investigate whether STI self-sampling should be made available as an additional approach to deliver STI testing services, whether incorporated into routine STI services or as an alternative model with linkage to care.