Abstract: Objective: To explore the characteristics and trends of syphilis infection in Shandong province, providing scientific evidence for the control strategy of syphilis. Methods: The data of the patients with syphilis from 16 prefecture-level cities in Shandong province from 2010 to 2019 were analyzed, including incidence, proportion, annual growth rate and distribution. Chi-square test was used to explore the incidence trend of syphilis. Results: The incidence of syphilis increased from 6.15 per 100 thousand in 2010 to 20.24 per 100 thousand in 2019, showing a year-on-year growth trend (χ2=12475.40, P<0.01), with an average annual growth rate of 14.15%. In particular, the cases of latent syphilis showed the fastest rate of growth, from 31.98% in 2010 to 74.28% in 2019. The high-incidence areas were Weihai, Qingdao in the eastern coastal area, and the Zaozhuang in the southern area, with an average annual incidence of more than 20 per 100 thousand person-years. The number of female patients was higher than that of males, with an average male/female ratio of 0.89∶1. The peak age was 20-35 years, accounting for 39.41%, and the incidence increased the fastest in the cases of 60-79 years, with an average annual growth rate of 22.82%. Of the 20 occupational groups, peasant was the most (43.94%). Conclusion: The incidence of syphilis, especially latent syphilis, in Shandong Province increase rapidly. It is necessary to strengthen the screening of syphilis, especially in the high incidence areas and high incidence population.

Key words: syphilis, epidemiology, sexually transmitted infections