Abstract: 【Abstract】 Objective To investigate epidemiological trend and characteristics of genital Chlamydia trachomatis （Ct） infection in China in recent years, and to provide evidence for making Ct infection prevention and control strategies. Methods A descriptive epidemiological study was conducted to analyze personal, spatial and temporal distribution of genital Ct infection cases reported from 105 national sexually transmitted disease （STD） surveillance sites in China from 2015 to 2019. Results The reported incidence rate of genital Ct infection increased from 37.18 per 100 000 in 2015 to 55.32 per 100 000 in 2019, with the average annual rate of increase being 10.44%. The reported incidence rates at national STD surveillance sites ranged from 0 to 1 309.38 per 100 000, which were relatively high in Zhejiang, Guangdong, Guangxi and Hainan provinces. Increasing trends in the reported incidence rate were observed among both females and males. From 2015 to 2019, the reported annual incidence rate in males was lower than that in females, and the male-to-female reported incidence rate ratio decreased from 0.43 （22.57 per 100 000 vs. 52.74 per 100 000） in 2015 to 0.32 （27.35 per 100 000 vs. 84.55 per 100 000） in 2019. The reported incidence rates increased yearly in the groups aged more than 15 years, and the average annual rate of increase was highest in the group aged 20 - 24 years （25.81%）, followed by the group aged 15 - 19 years （22.55%）; the sexually active population aged 20 - 34 years showed the highest reported incidence rate among all the age groups, and the reported incidence rate was up to 184.70 per 100 000 in this age group in 2019. Genital Ct infection cases were reported among all occupation groups, and the largest proportion of cases was found in unemployed population（32.86% - 38.50%）, followed by commercial service population（25.29% - 27.84%）. General hospitals reported the largest number of genital Ct infection cases （68.30% - 74.59%）, followed by maternal and child health hospitals. Conclusions The reported incidence rate of genital Ct infection was high with an increasing trend in China from 2015 to 2019, and the southeastern coastal provinces of China showed a relatively high repoted incidence rate. Genital Ct infection affected a wide range of people in different occupations. The reported incidence rate in females was higher than that in males, and the population with a high incidence tended to be younger.

Key words: Chlamydia trachomatis, Reproductive tract infections, Incidence, Epidemiology, Sentinel surveillance