HIV prevalence in sex workers

Export Indicator

Percentage of sex workers who are living with HIV
What it measures

It measures progress on reducing HIV prevalence among sex workers.

Rationale

Sex workers typically have higher HIV prevalence than the general population in both concentrated and generalized epidemics. In many cases, prevalence among these populations can be more than double the prevalence among the general population. Reducing prevalence among sex workers is a critical measure of a national-level response to HIV.
Countries with generalized epidemics may also have a concentrated sub-epidemic among sex workers. If so, it is valuable to calculate and report on this indicator for this population.

Numerator

Number of respondents who test positive for HIV.

Denominator

Number of respondents tested for HIV.

Calculation

Numerator / Denominator

Method of measurement

UNAIDS and WHO Working Group on Global HIV/AIDS and STI Surveillance: Guidelines among populations most at risk for HIV (WHO/UNAIDS, 2011).
This indicator is calculated using data from HIV tests conducted among respondents in the primary sentinel site or sites.
The sentinel surveillance sites used for the calculation of this indicator should remain constant to allow for the tracking of changes over time.
Disaggregation:
• Sex (female, male, transgender)
• Age (<25/25+)

Measurement frequency

Annual

Disaggregation

Age-group:

< (less than) 25 years

> (greater than) 25 years

Gender:

Female

Male

Strengths and weaknesses

In theory, assessing progress in reducing the occurrence of new infections is best done through monitoring changes in incidence over time. However, in practice, prevalence data rather than incidence data are available. In analyzing prevalence data of sex workers for the assessment of prevention programme impact, it is desirable not to restrict analysis to young people but to report on those persons who are newly initiated to behaviours that put them at risk for infection (e.g. by restricting the analysis to people who have or participated in sex work for less than one year) This type of analysis also has the advantage of not being affected by the effect of ART in increasing survival and thereby increasing prevalence.
If prevalence estimates are available disaggregated by greater than and less than one year in sex work countries are strongly encouraged to report this disaggregation in their Country Progress Report, and to use the comments field in the reporting tool for this indicator to present disaggregated estimates.
Due to difficulties in accessing sex workers, biases in sero-surveillance data are likely to be far more significant than in data from a more general population, such as women attending antenatal clinics. If there are concerns about the data, these concerns should be reflected in the interpretation.
An understanding of how the sampled population(s) relate to any larger population(s) sharing similar risk behaviours is critical to the interpretation of this indicator. The period during which people belong to a key population is more closely associated with the risk of acquiring HIV than age. Therefore, it is desirable not to restrict analysis to young people but to report on other age groups as well.
Trends in HIV prevalence among sex workers in the capital city will provide a useful indication of HIV-prevention programme performance in that city. However, it will not be representative of the situation in the country as a whole.
The addition of new sentinel sites will increase the samples representativeness and will therefore give a more robust point estimate of HIV prevalence. However, the addition of new sentinel sites reduces the comparability of values. As such it is important to use consistent sites when undertaking trend analyses.
If the data are subnational, please provide the disaggregation by administrative area in the comment field. Please submit the digital version of any available survey reports using the upload tool.
Several countries have in previous reporting rounds reported HIV prevalence among subpopulations of transgender women through the additional comments field in the GARPR online reporting tool. This demonstrates that the data are feasible to obtain in different settings.

Further information

For further information, please consult the following links:

http://www.unaids.org/en/HIV_data/Methodology/default.asp
Revised guidelines on HIV surveillance for key populations at higher risk: WHO/UNAIDS Working Group on Global HIV/AIDS and STI Surveillance. Guidelines on surveillance among populations most at risk for HIV. Geneva, UNAIDS, 2011 (http://www.unaids.org/en/media/unaids)
contentassets/documents/epidemiology/2011/20110518_Surveillance_among_most_at_risk.pdf
Operational Guidelines for Monitoring and Evaluation of HIV Programmes for Sex Workers, Men who have Sex with Men, and Transgender People. MEASURE Evaluation (www.cpc.unc.edu/measure/publications/ms-11-49a).