Objective To evaluate spatiotemporal clustering and incidence intensity of hand, foot and mouth disease (HFMD) in children under 6 years old in Nanjing, Jiangsu province, and provide reference for graded early warning, prevention and control of HFMD.

Methods Based on the surveillance data of HFMD in children under 6 years old in Nanjing during 2014−2023, Joinpoint regression model was used to describe the incidence trend, while spatiotemporal scanning was conducted to explore the spatiotemporal clustering of the cases, and moving epidemic method (MEM) was used to evaluate the incidence intensity in 2024.

Results The annual incidence of HFMD showed no significant decline (average annual percent change =−10.61, 95% confidence interval: −21.52−1.83, P=0.082). The spatiotemporal clustering existed in each year, typeⅠclustering frequently occurred in 15 streets/townships of Lishui and Gaochun districts in southern Nanjing from February to May, and from October to January. Moreover, the MEM based on the weekly incidence data from 2014 to 2019 and 2023 indicated that incidence of week 8−35 in 2024 was less than pre-epidemic threshold (91.50/100 000).

Conclusion There was no significant decrease in annual incidence of HFMD in children under 6 years old in Nanjing, incidence intensity and spatiotemporal clustering were not completely consistent in each year, the grading prevention and control of HFMD should be carried out according to the incidence intensity.