[Epidemiological trends and spatiotemporal distribution of syphilis in youth aged 15-24 years in Guangzhou, 2005-2024].

Objective: To analyze the epidemiological trend and spatial-temporal distribution of syphilis in young people aged 15-24 years in Guangzhou from 2005 to 2024, and compare the differences in epidemiological characteristics between the student group and the non-student group. Methods: The syphilis surveillance data in young people aged 15-24 years in Guangzhou from 2005 to 2024 were collected through Chinese Information System for Disease Control and Prevention. The student's group and the non-students' group were classified according to occupation registration. Joinpoint regression model was used to analyze the trend of annual incidence. Bayesian structural time series model was used to analyze the seasonal changes and softwareArcGIS 10.2 was used for global spatial autocorrelation analysis and local hotspot analysis. Results: The reported incidence increased from 15.17/100 000 in 2005 to 55.74/100 000 in 2024, with an average annual percentage change (AAPC) of 7.28% (P<0.001). The incidence of latent syphilis showed an upward trend (AAPC=10.37%, P<0.001). The incidence increase in age group 15-19 years (AAPC=11.66%, P<0.001) was greater than that in age group 20-24 years (AAPC=6.36%, P<0.001). The upward trend of incidence in the non-student group (AAPC=11.68%, P<0.001) was greater than that in the student group (AAPC=8.71%, P<0.001). The cases were mainly non-students (94.52%), individuals aged 20-24 years (75.67%), and people with latent syphilis (68.07%). The incidence peak in the student group occurred in November, and the incidence peaks in the non-student group occurred in May and during July - September. Positive spatial autocorrelation in syphilis case counts was observed among the overall youth population and non-students in 2019 and 2021-2024, while syphilis cases among students showed positive spatial autocorrelation over the 2005-2024 period (Z=2.571, P=0.010). The hot spots of the youth group and the non-student group were in Baiyun, Huadu and Panyu district. of Guangzhou, and the hotspots of the non-student group were distributed in Baiyun District, while the hotspots of the student group were distributed in Tianhe District. Conclusions: The reported incidence of syphilis in young people aged 15-24 years increased in Guangzhou from 2005 to 2024, and the change patterns of spatiotemporal distribution of syphilis in students and non-students varied. It is necessary to strengthen the screening of non-student groups in the floating population and improve the screening and follow-up in summer when the incidence is high, strengthen the monitoring for the student group in colleges and universities, and carry out health education and intervention after the holiday.