Percentage of sex workers (SWs) with active syphilis
Testing sex workers (SWs) is important for their health, and for second generation surveillance purposes.
Progress in decreasing high-risk sexual behaviour, and intervention efforts to control syphilis among sex workers.
Number of sex workers who tested positive for active syphilis
Number of sex workers who were tested for active syphilis
Numerator / Denominator
Measurement tools: Data from routine health information systems, sentinel surveillance or special surveys may be used.
How to measure: The traditional approach to determining seroprevalence has been to screen with a non-treponemal test that measures reaginic antibody (e.g., VDRL or RPR) and confirm positive results with a treponemal test that measures treponemal antibody (e.g., TPHA, TPPA, EIA, or rapid treponemal test). Newer, rapid treponemal tests are comparatively easy to use, a feature which encourages the use of these tests for screening, ideally paired with a non-treponemal test that detects reaginic antibody. Whichever approach is used, the proposed indicator requires both a positive non-treponemal test AND a positive treponemal test to give a proxy for active infection. If RPR testing is performed, it should be titrated and be ≥1:8 to be certain of active syphilis.
Just a non-treponemal test, or just a treponemal test, while useful in some situations for therapeutic purposes, is not sufficiently specific for surveillance of sex workers. The requirement for both a positive non-treponemal test and a positive treponemal test in sex workers differs from the indicator on syphilis testing in antenatal care attendees because sex workers are more likely to have a history of previous infection. A positive treponemal test measures lifetime exposure, whereas the non-treponemal test is a better indicator of active infection.
Data Quality Control and Notes for the Reporting Tool
It is important NOT to count multiple tests run on the same patient. That is, if a person has been tested more than once in the past 12 months, they should not be counted more than once.
Gender: Male, Female
Strengths: Requiring testing by both tests enhances specificity of the reported numbers of positive tests. In addition, requiring testing by both tests will increase the likelihood of identifying active disease.
Weaknesses: Requiring testing by both tests increases the difficulty of acquiring data for this indicator.
Quality assurance and quality control should be an integral part of syphilis testing to ensure reliable results.
Look at trends in comparable groups over time. Compare with data on trends of syphilis and HIV where available.