Syphilis prevalence among pregnant women

Export Indicator

Percent of blood samples taken from women aged 15-24 that test positive for syphilis by Rapid Plasma Reagin (RPR) testing during routine sentinel surveillance at selected antenatal clinics.
What it measures

STIs are transmitted in the same ways as HIV, and will be prevented by the same safe behaviours being promoted by HIV prevention programmes. Because bacterial STIs are curable, STIs will usually reflect more recent risk behaviour than HIV, which stays with an infected person until death. All the more so because HIV prevention programmes aim to increase recognition and treatment of STIs besides HIV. So measures of STI prevalence are a relatively good guide to recent trends in sexual risk behaviour.

Rationale
Numerator

Number of blood samples from women aged 15-24 testing positive for syphilis

Denominator

Total number of blood samples from women aged 15-24 tested for syphilis

Calculation
Method of measurement

Most countries regularly test pregnant women attending antenatal clinics for syphilis with RPR tests in order to treat those infected and prevent neonatal syphilis infection in infants. Indeed it is blood taken for the purpose of routine syphilis screening and treatment of pregnant women that provides the ethical justification for unlinked anonymous HIV testing of leftover blood. Syphilis screening, therefore, ought to be conducted throughout the year in all antenatal clinics nation-wide. However, reporting systems can be erratic and testing quality difficult to ensure. Linked samples must be tested for syphilis so that a woman can be appropriately treated. However for the purposes of constructing this indicator, it is recommended that blood samples sent to a central laboratory for unlinked anonymous testing of HIV are also re-tested for syphilis. This ensures consistency between data sets regarding site selection and sample collection period, and facilitates quality control. In calculating this indicator, countries with strong health information systems may wish to include data on syphilis prevalence from a wider selection of antenatal sites than just those included in the sentinel surveillance system for HIV. It is strongly recommended that two separate figures be reported for syphilis prevalence: one for women aged 15-24 and one for women across the whole reproductive age range of 15- 49. The indicator is the number of blood samples from women aged 15-24 testing positive for syphilis divided by the total number of blood samples from women aged 15-24 tested for syphilis.

Measurement frequency
Disaggregation

Age group: 15 years - 24 years, 15 years - 49 years

Condom type: N/A

Education: N/A

Gender: N/A

Geographic location: N/A

HIV status: N/A

Pregnancy status: N/A

Sector: N/A

Service Type: N/A

Target: N/A

Time period: N/A

Type of orphan: N/A

Type/Timing of testing: N/A

Vulnerability status: N/A

Explanation of the numerator
Explanation of the denominator
Strengths and weaknesses

Since syphilis is curable, infection tested by RPR probably reflects relatively recent infection. It is therefore recommended that it be measured for women across the whole reproductive age range of 15-49 to give an idea of ongoing risk behaviour. It is, however, recognised that the indicator will be biased to a certain extent by the association between syphilis and infertility. For programme purposes, especially in order to track changes in risk behaviour among young people, the data should also be disaggregated by age group and presented for 15-19, 20-24 and 15-24 as well as for the entire 15-49 year age range.

Further information