Legalisation of sex work associated with lower prevalence of HIV in sex workers

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Countries that have legalised some aspects of sex work have fewer sex workers living with HIV than countries that criminalise all aspects of sex work, according to an ecological analysis of 27 European countries published online ahead of print in The Lancet HIV.

The association remained statistically significant after adjustment for countries’ economic development, HIV prevalence, antiretroviral therapy coverage and proportion of sex workers who inject drugs.

“Our findings suggest that the legalisation of some aspects of sex work might help reduce HIV prevalence in this high-risk group, particularly in countries where the judiciary is effective and fair,” say Aaron Reeves and colleagues.



In HIV, usually refers to legal jurisdictions which prosecute people living with HIV who have – or are believed to have – put others at risk of acquiring HIV (exposure to HIV). Other jurisdictions criminalise people who do not disclose their HIV status to sexual partners as well as actual cases of HIV transmission. 


A tentative explanation for an observation, phenomenon, or scientific problem. The purpose of a research study is to test whether the hypothesis is true or not.


When using a diagnostic test, the probability that a person who does have a medical condition will receive the correct test result (i.e. positive). 

statistical significance

Statistical tests are used to judge whether the results of a study could be due to chance and would not be confirmed if the study was repeated. If result is probably not due to chance, the results are ‘statistically significant’. 


Improvement in a tumour. Also, a mathematical model that allows us to measure the degree to which one of more factors influence an outcome.

Although the prevalence of HIV tends to be higher in sex workers than in the general population, prevalence varies between European countries, suggesting that structural factors might play a part.

Structural determinants of HIV risk include sex work policy, particularly laws that criminalise buying, selling, or procuring sex. They may increase HIV risk through recurrent police harassment, violence, and arrests or fear of arrests of female sex workers or clients, which can perpetuate unsafe working conditions, drug use risks, and physical or sexual violence against sex workers without recourse. Such insecurity can make it more difficult for sex workers to negotiate condom use, especially if condoms can be used as evidence in judicial proceedings.

27 European countries

The researchers say they are the first to take advantage of the diversity of legal frameworks between European countries “to test the hypothesis that legalisation of some aspects of sex work is associated with decreased HIV prevalence among sex workers when compared with countries that retain criminal laws”.

Data come from 27 countries in which the European Centre for Disease Prevention and Control have an estimate of the proportion of sex workers living with HIV. Although two countries’ estimates do include male sex workers, their numbers are so small that the analysis essentially pertains to female sex workers.

In one group of countries, such as Lithuania and Romania, all aspects of sex work are criminalised.

In another group of countries, including the UK, Italy and Bulgaria, the buying and selling of sex has been legalised, but procurement through brothels or pimping is criminalised.

In addition, two countries in the data set, Sweden and Norway, have legalised selling sex but have criminalised buying sex. Despite the intent of this ‘Nordic model’ to shift criminalisation from sex workers to customers, many advocates say that it continues to make sex workers vulnerable.

Finally, one country – Germany – has legalised most forms of sex work and regulated the industry.

The researchers also investigate whether more effective and fair law enforcement mediates the relation between sex work policy and HIV prevalence. They use a World Bank indicator of the rule of law in countries, which captures the confidence the general population has in the effectiveness and fairness of the judiciary and police. However, this indicator does not specifically measure sex workers’ experience of policing.

The researchers used ecological linear regression models to test the possible relationships.


In countries where sex work is partly legalised, sex worker HIV prevalence was lower than in countries where sex work is criminalised (β= -2.09). Specifically, the average prevalence in ten countries where the practice is illegal was 4.0%, compared to 0.5% in 17 countries where some aspects of sex work have been legalised.

HIV prevalence remained lower in countries that legalise some aspects of sex work after adjusting for gross domestic product (β= -1.86) and after adjusting for the prevalence of injecting drug use among sex workers (β= -1.93). Neither GDP nor the proportion of sex workers who inject drugs was associated with HIV prevalence after controlling for sex work policy.

Germany, the one country which has legalised all aspects of sex work had a lower prevalence (after adjustment) than countries with more restrictive policies, although it is hard to generalise on the basis of one case. It is also hard to draw specific conclusions about the two ‘Nordic model’ countries, especially as data were collected in Norway before the introduction of this law in 2009.

Effective and fair law enforcement did not make any difference to these associations in countries which criminalise all aspects of sex work. But effective and fair law enforcement was associated with a lower HIV prevalence in countries that have legalised some aspects of sex work (β= -0.63). This suggests that legalisation in a context of the effective rule of law makes the most difference to sex workers' health.

To check that the findings were not skewed, a series of sensitivity analyses were done. The results did not qualitatively change.


Aaron Reeves and colleagues say that their findings are consistent with other studies that report that the removal of criminal laws protects sex workers, allowing them to enter the formal economy, to benefit from social insurance, and to receive protection from law enforcement. This may help increase access to condoms, reduce the risk of violence and empower sex workers in condom negotiation.

They also acknowledge the limitations of their study – in particular weaknesses in the data sources that can be analysed, including a lack of detailed data on how sex work laws and policies are implemented.

But in a linked comment article, Marie-Claude Boily and Kate Shannon commend the researchers for attempting to disentangle the independent effects of the law and enforcement. “Despite its limitations, this study provides useful ecological-level data across many European countries that should raise caution for governments and policy makers considering criminalised or end-demand models,” they say.


Reeves A et al. National sex work policy and HIV prevalence among sex workers: an ecological regression analysis of 27 European countries. The Lancet HIV, online ahead of print, 2017.

Boily MC & Shannon K. Criminal law, sex work, HIV: need for multi-level research. The Lancet HIV, online ahead of print, 2017.