Background In the context of rapid urbanisation and economic growth in China, places where social mixing intersects with commercial activities could play an important role in the formation of new partnerships and spread of sexually transmitted infections (STIs) including HIV. People who work at such venues may be at higher risk of STIs. A study was conducted from October 2009 through February 2010 in Liuzhou, China to estimate the prevalence of syphilis and related risk factors among females working at places where people go to meet new sexual partners.

Methods Using a two-stage venue-based sampling method called PLACE, data were collected through interviews with 656 females nested within 36 venues with a minimum of five females per venue. A venue was classified as a “sex venue” if the manager or at least one of the females reported solicitation of commercial sex at the venue in the past 4 weeks. All respondents were screened for syphilis onsite using a rapid treponemal-specific test which represents lifetime syphilis infection acquired at anytime. Multi-level regression modelling was used to examine individual and venue correlates of syphilis infection and to account for clustering.

Results 23 of the 36 venues were classified as sex venues. Among all females, those working at sex venues and at venues with no report of sex work, the weighted lifetime syphilis prevalence was 5.8%, 16.3%, 0.5% respectively and the reported average number of new sexual partners in the past 4 weeks was 1.5, 4.4, 0.1 respectively. After adjusting for other individual characteristics and clustering, two venue-level factors, that is working at sex venues (AOR 24.0, 95% CI 2.5 to 227.6), working in venues located in rural counties (AOR 3.6, 95% CI 1.2 to 10.9), and two individual correlates, ie, self-report of sex work (AOR 2.3, 95% CI 1.0 to 5.3) and being in elder age groups (AOR 7.0, 95% CI 1.5 to 32.2) were significantly associated with risk of lifetime syphilis infection.

Conclusions Females working at social venues had a high rate of new sexual partner acquisition and a high prevalence of lifetime syphilis infection. Females working at sex venues or venues located in rural counties were at relatively high risk of syphilis infection, despite whether they reported engaging in sex work. An intervention strategy focused on the places where social mixing occurs rather than risk group status may contribute to the prevention and control of HIV/STIs in China.