Epidemiological and etiological characteristics of hand-foot-mouth disease in Hangzhou， Zhejiang Province， 2010‒2023

Objective To analyze the epidemiological characteristics and trends of hand-foot-mouth disease (HFMD) in Hangzhou, so as to provide an evidence for developing effective prevention and control measures and evaluating the control effects.

Methods The incidence data of HFMD in Hangzhou were collected from the Infectious Disease Reporting Information Management System of China Information System for Disease Control and Prevention. Descriptive epidemiology was applied to analyze the temporal, spatial and demographic distribution characteristics and etiology monitoring results of HFMD cases in Hangzhou from 2010 to 2023. Joinpoint regression model was used to analyze the trends of incidence rate of HFMD. Furthermore, circular distribution method was utilized to calculate the incidence peak of HFMD.

Results From 2010 to 2023, the average annual reported incidence rate of HFMD in Hangzhou was 138.85/100 000, the proportion of severe cases was 0.04%, the mortality rate was 0.01/100 000, and the case fatality rate was 5.30/100 000. Both the total incidence rate and the incidence rate by sex showed an increasing trend. The annual reported incidence rate in males (158.72/100 000) was higher than that in females (117.61/100 000). The reported incidence rate showed a significant seasonal characteristic, with summer being the peak of epidemic. The results of surveillance samples suggested that the prevalence of HFMD in Hangzhou is characterized by the co-existence of multiple pathogens, with EV-A71 and CV-A16 being the dominant pathogens in the previous years and CV-A6 being the dominant pathogen since 2018. The proportion of EV-A71 in severe cases (77.19%) was higher than that in ordinary cases (15.37%), in addition, its proportion in ordinary cases, severe cases, and fatal cases all showed a decreasing trend.

Conclusion The incidence rate of HFMD in Hangzhou is still high, so it’s still necessary to continue to strengthen the prevention and control measures for key populations. In recent years, CV-A6 has been the main prevalent pathogen in Hangzhou. Further efforts in pathogen detection and analysis should be enhanced in the future.