BACKGROUND: The ANRS 12381 PRINCESSE study is an interventional single-arm cohort. Participants recruitment started in November 2019. The study aimed to evaluate a comprehensive and community-based care offer among FSWs aged '¥ 18 years in the San Pedro area. METHODS: Care services included quarterly syndromic screening for STIs, as well as vaginal and anal swabs for the screening of chlamydia trachomatis (CT) and neisseria gonorrhoea (NG) by polymerase chain reaction (PCR) at M0, M12 and M24. At the same visits, identification of dysplasias and precancerous lesions of the cervix was performed by visual inspection after applying acetic acid and Lugol's iodine. STIs were managed according to the national algorithm. We describe (i) the characteristics of cervical lesions as well as the prevalence of STIs (syndromic and PCR) and associated symptoms and (ii) the incidence of syndromic STIs during follow-up. RESULTS: In November 2021, 372 FSWs were included. The median age was 29 years, 34% had never been to school, 56% were Ivorian, and the median duration of sex work was 2 years. At inclusion, 4.7% [95% confidence interval: 2.8-7.5] had cervical lesions with 3.5% leukoplakia and 2.2% haemorrhagic cervical junction zone. The prevalence of syndromic STIs was 17.2% [13.0-22.6]; associated clinical signs were vaginal discharge (13.7%), vaginal ulceration (2.1%), lower abdominal pain (4.3%) and cervical inflammation (2.6%). The prevalence of anovaginal CT and NG were 8.7% [6.2- 12.1] and 10.4% [7.6- 13.9], respectively; clinical signs were found in 2.4% of CT-positive and 12.2% of NG-positive FSWs. Most FSWs with syndromic STIs did not have CT or NG infection. During the follow-up, 82 cases of syndromic STIs were observed per 209 person-years, i.e. an incidence of 39.1% [31.1- 49.0]. PCR data at M12 and M24 are being consolidated and will allow estimating the incidence of CT and NG. CONCLUSIONS: A high prevalence and incidence of syndromic STIs were observed among FSWs, highlighting the importance and the interest of a regular follow-up. The results also showed the predominantly asymptomatic nature of STIs discovered by PCR in this at-risk population and, therefore, the importance of coupling syndromic screening and PCR analyses.