Remarks

• Integration: SST, as with all testing approaches, should be offered within a broader programme and package of services, which includes ensuring access and linkage to further testing (where available) and immediate treatment initiation. Opportunities to integrate syphilis self-testing into and/or to expand existing services should be a priority.
• Quality-assured products: SST may include products such as dual HIV/syphilis self-tests, treponemal self-tests and dual treponemal/non-treponemal self-tests. As with all testing approaches, SST should be conducted using quality-assured products.
• Epidemiology and context: Policymakers and implementers need to have a clear understanding that SST can be reactive with any current or prior infection by any treponematosis (e.g., syphilis, yaws, bejel or pinta) when determining how and where to deliver self-testing to specific populations and in certain geographies.
• Clear messages: Self-testers need to be provided with clear guidance about when they should test themselves, how to interpret their self-test results and, if needed, where to go for further testing and treatment. These further services are particularly critical when single treponemal self-tests are used that cannot differentiate previously treated infections from current infections. In endemic areas, it is critical to clarify that reactive serologic tests cannot differentiate between syphilis and other treponematosis (e.g., yaws). Self-testers may also need support tools to ensure they know how to self-test, and this can include instructions for use, videos, in-person demonstrations and support from peers or community health workers. Information about testing with a partner should also be provided, when appropriate, to encourage use of partner services. Self-testing refers to a process whereby people collect their own specimen using a simple rapid test and then perform the test and interpret their results when and where they want. WHO recommends a range of self-testing approaches which can improve access to and uptake of testing services, including those for pregnancy (40), HIV (11), HCV (41), syphilis and COVID-19 (42) (see for example, Figure 5.1). New dual self-tests, which can detect syphilis and HIV infection at the same time, are also recommended (43). See Box 5.8 for a summary of self-testing recommendations. Self-testing has been consistently shown to be safe, acceptable, and effective in increasing the number of people tested, diagnosed with and treated. While efforts to optimize linkage are important, studies have consistently shown that linkage rates following self-testing continue to be high and comparable to standard testing (44-46). The empowering nature of self-testing has also enabled people, including partners and people with limited contact with the health system, to access testing along with onward prevention, care and treatment services. Self-tests could be distributed through pharmacies, vending machines, pick-up from a local store, distribution by peers, community-based distribution, online ordering, mail delivery and facility-based distribution. Self-testing can enable greater flexibility for clients and health services, particularly as part of simplified implementation of PrEP and PEP services (3). A range of support tools can be utilized to support self-testing implementation (47), including virtual interventions and artificial intelligence (48). Evidence has shown that both blood-based and oral fluid-based self-tests are acceptable, and different users have different preferences (49-60). There is currently no evidence that there are differences in user uptake when offering either blood-based or oral fluid-based self-tests. There are currently a range of affordable WHO prequalified self-tests that can be accessed: https:// extranet.who.int/prequal/vitro-diagnostics/prequalification-reports/whopr.