Why do surveys show that female sex workers have 14 times the risk of having HIV as other women?

Cheryl Overs, Monash University © IAS/Steve Shapiro - Commercialimage.net
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Although researchers and public health organisations in most low and middle income countries have not collected any recent data on the prevalence of HIV in female sex workers, the data that do exist are alarming, the 19th International AIDS Conference (AIDS 2012) heard on Thursday.

Pooling the data available for 50 countries, female sex workers have a 14-fold higher risk of infection as women of a similar age in the general population.

Rates are especially elevated in some countries, including Bangladesh, Benin, Cambodia, China, Guinea, Guyana, India, Indonesia, Malaysia, Mauritius, Mexico, Nepal and Senegal.


middle income countries

The World Bank classifies countries according to their income: low, lower-middle, upper-middle and high. There are around 50 lower-middle income countries (mostly in Africa and Asia) and around 60 upper-middle income countries (in Africa, Eastern Europe, Asia, Latin America and the Caribbean).

treatment as prevention (TasP)

A public health strategy involving the prompt provision of antiretroviral treatment in people with HIV in order to reduce their risk of transmitting the virus to others through sex.

systematic review

A review of the findings of all studies which relate to a particular research question and which conform to pre-determined selection criteria. 


A product (such as a gel or cream) that is being tested in HIV prevention research. It could be applied topically to genital surfaces to prevent or reduce the transmission of HIV during sexual intercourse. Microbicides might also take other forms, including films, suppositories, and slow-releasing sponges or vaginal rings.

structural factors

Social forces which drive the HIV epidemic and create vulnerability to HIV infection. They include gender inequality and violence, economic and social inequality, and discriminatory legal environments.

Other surveys in well-resourced countries like Australia, however, have found HIV prevalence in female sex workers that differs little from that in other women. The conference also heard advocates describe what is required to change this situation.

“The epidemic is not driven by the lack of a pill or a gadget, the epidemic is driven by repression,” Cheryl Overs told a plenary session. “Sex workers from Sweden to Singapore to Swaziland all say that the greatest threat to their health and human rights is the law that makes it impossible to find safe places to work, and prevents them from having the same protections as other workers and other citizens.”

In many countries, the needs of sex workers remain ignored and under-researched. Stefan Baral, Deanna Kerrigan and colleagues from the Johns Hopkins Bloomberg School of Public Health – the same group that has taken a lead in highlighting elevated HIV rates in men who have sex with men around the world – conducted a systematic review and meta-analysis to pull together estimates of HIV rates in low and middle income countries.

They were able to include 102 reports which met pre-determined quality criteria, encompassing 12,197 sex workers. All reports came from 2007 to 2011.

But reports were only available for 50 of 145 countries. “We must look critically at the global policy environment which limits comprehensive assessments of HIV prevention and service delivery needs of sex workers across settings,” commented Deanna Kerrigan.

The available data do show that women who sell sex are at particularly high risk of infection. Kerrigan noted that their increased vulnerability is not just due to behavioural factors (large numbers of sexual partners, etc.) but also structural factors (criminalisation, human rights violations, etc.).

Data were available for 14 Asian countries. Whereas HIV prevalence in women aged 15-49 in these countries is 0.18%, for sex workers it is 5.2%, meaning their risk of having HIV is 29 times greater.

In sub-Saharan Africa, data were available for 16 countries. Whereas HIV prevalence for women in the general population is 7. 4%, it is 36.9% for women who sell sex, meaning their risk is 12 times greater.

In Latin America and the Caribbean, there were data for 12 countries. With a background female HIV prevalence of 0.4% and 6.1% for women who sell sex, their risk is also 12 times greater.

In the Middle East and North Africa, 1.7% of female sex workers had HIV. In Eastern Europe, prevalence was 10.9%. However because data were only available for a handful of countries in these regions, further analysis was not felt to be reliable.

The data show wide variations from country to country, and sometimes between different regions of the same country. Some of this is likely due to different sampling and research methods.

Deanna Kerrigan concluded that “these data represent a call for action to invest in and address the needs of sex workers to prevent HIV, including evidence-based comprehensive HIV prevention strategies which protect and promote their human rights”.

These data are a call for action to invest in and address the needs of sex workers

Moreover, the same group of researchers also reported the results of modelling work which estimated the impact of providing such prevention strategies. Two strategies were examined:

  • Improving sex workers’ access to antiretroviral therapy so that coverage is the same as for other adults in their country.
  • A comprehensive community-empowerment programme, in which structural barriers are addressed collectively. The programme typically includes community organising and mobilising, peer education, condom distribution and more accessible clinical services for sexually transmitted infections.

A soon to be published systematic review conducted for the World Health Organization has found that community empowerment programmes typically reduce inconsistent condom use by half. The Johns Hopkins researchers applied this finding to the epidemics of Brazil, Kenya, Thailand and Ukraine.

For example, in Kenya, just improving ART access would reduce infections in sex workers by 25% over five years. Only making the empowerment intervention available to two thirds of sex workers would reduce infections by 11.5%. Doing both would reduce infections by 33%.

There would also be a significant impact on the epidemic in the wider population, with 30% fewer infections if the interventions were combined.

Although it may appear that the ART intervention makes the greater difference, the researchers note that empowerment and reduced structural barriers are probably a necessary requirement for expanded ART access. Indeed, the interaction between ART use and empowerment had not been fully accounted for in the model.

“Is there really a product or a medicine that can change the balance of power between sex workers and their clients?" Cheryl Overs

The sex worker activist and researcher Cheryl Overs spoke to these issues at a plenary that morning. In particular, she commented on the conference’s ‘turning the tide together’ slogan.

While a video showed waves washing up on a beach, she said that the tide is made up of many waves – including social exclusion, lack of legal rights, family rejection, poverty, bad working conditions, violence, condoms used as evidence and corruption.

“The waves are interconnected, so there’s no selecting which waves to turn back,” she said. “Involving and empowering sex workers is crucial to turning that tide.” However many sex workers have been prevented from participating in the Washington DC conference, due to bans on them entering the United States.

Overs pointed to the Global Commission on HIV & the Law’s recommendations for governments on treating sex workers in a way that is consistent with human rights obligations.

And she commented on what treatment as prevention, microbicides and pre-exposure prophylaxis (PrEP) could offer sex workers. “Is there really a product or a medicine that can change the balance of power between sex workers and their clients?” she asked.

She warned that the cost and responsibility of using the new methods will continue to fall on sex workers, who will still need protection from sexually transmitted infections and pregnancy. HIV testing is the gateway to new prevention methods, but forced testing and breaches of confidentiality are already commonplace for sex workers.

“I haven't raised these issues about new prevention technologies to suggest that they can't work for sex workers,” Overs said. “I raised them to illustrate that they create challenges that can't be solved without strong inputs from sex worker advocates.”

To those rolling out treatment as prevention and PrEP she said: “You need to focus more on the challenges in the broader environment of sex work, not just on getting the products to sex workers.”


Baral S et al. High and disproportionate burden of HIV among female sex workers in low- and middle-income countries: a systematic review and meta-analysis. 19th International AIDS Conference, abstract THAC0501, 2012.

The data were simultaneously published in a journal:

Baral S et al. Burden of HIV among female sex workers in low-income and middle-income countries: a systematic review and meta-analysis. Lancet Infectious Diseases 12: 538-549, 2012. (Free registration needed to read full text).

Wirtz AL et al. Modeling the impacts of a comprehensive community empowerment-based, HIV prevention intervention for female sex workers in generalized and concentrated epidemics: infections averted among sex workers and adults. 19th International AIDS Conference, abstract THAC0502, 2012.

Wirtz AL et al. Modeling the impacts on HIV infection among female sex workers via the expansion of antiretroviral therapy among all adults. 19th International AIDS Conference, abstract TUPE182, 2012.

Overs C. The Tide Cannot Be Turned Without Us:  HIV Epidemics Amongst Key Affected Populations. 19th International AIDS Conference, THPL0102, 2012.