Effects of government registration on unprotected sex amongst female sex workers in Tijuana; Mexico

BackgroundSex work is partially regulated in Tijuana, but little is known of its health effects. A recent behavioural intervention amongst female sex workers (FSWs) decreased incidence of HIV/STIs by 40%. We evaluated effects of sex worker regulation on condom use amongst FSWs randomized to this intervention.MethodsFSWs aged ≥18 years who reported unprotected sex with ≥1 client in the last 2 months and whether they were registered with Tijuana's Municipal Health Department underwent a brief, theory-based behavioural intervention to increase condom use. At baseline and 6 months, women underwent interviews and testing for HIV, syphilis, Chlamydia trachomatis and Neisseria gonorrhoeae. Negative binomial regression was used to determine the effect of registration on numbers of unprotected sex acts and cumulative HIV/STI incidence.ResultsOf 187 women, 83 (44%) were registered. Lack of registration was associated with higher rates of unprotected sex (rate ratio: 1.7, 95% CI: 1.2–2.3), compared to FSWs who were registered, after controlling for potential confounders.ConclusionsRegistration predicted increased condom use amongst FSWs enrolled in a behavioural intervention. Public health programmes designed to improve condom use amongst FSWs may benefit from understanding the impact of existing regulation systems on HIV risk behaviours.