Active syphilis among sex workers

Export Indicator

Percentage of sex workers with active syphilis
What it measures

Progress in decreasing high-risk sexual behaviour and intervention efforts to control syphilis among sex workers

Rationale

Testing sex workers for syphilis is important for their health and for second-generation surveillance purposes.

Numerator

Number of sex workers who tested positive for active syphilis

Denominator

Number of sex workers who were tested for active syphilis

Calculation

Numerator/denominator

Method of measurement
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 (such as VDRL or RPR) and confirm positive results with a treponemal test that measures treponemal antibody (such as TPHA, TPPA, enzyme immunoassay or rapid treponemal test). Newer, rapid treponemal tests are comparatively easy to use, 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.
 
Just a non-treponemal test, or just a treponemal test, although 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 among 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 better indicates active infection.
Disaggregation

Gender (male, female and transgender)

Strengths and weaknesses
Strengths. Requiring testing using both non-treponemal and treponemal tests enhances the specificity of the reported numbers of positive tests. In addition, requiring testing using both tests increases the likelihood of identifying active disease.
 
Weaknesses. Requiring testing using both tests increases the difficulty of acquiring data for this indicator.
Further information
Quality assurance. Quality assurance and quality control should be an integral part of syphilis testing to ensure reliable results.
 
Use of the data. Look at trends in comparable groups over time. Compare with data on the trends in syphilis and HIV if these are available.
 
Quality control of data and notes for the reporting tool. Please describe what type of sex workers the data represent and the setting in which the data were collected in the comments field. Do not count multiple tests run on the same person: if a person has been tested more than once in the past 12 months, they should not be counted more than once.