Epidemiological characteristics of reinfection of pathogens causing hand, foot and mouth disease and influential factors in Jingzhou, Hubei, 2009−2022

  Objective  To analyze the epidemiological characteristics of reinfection of pathogens causing hand, foot and mouth disease (HFMD) and influential factors in Jingzhou, Hubei province, and provide scientific evidence for the prevention of HFMD.

  Methods  The incidence data of HFMD in Jingzhou from January 1, 2009 to June 30, 2022 were collected from the infectious disease surveillance system, and the information of the reinfection cases were obtained. Descriptive epidemiological method was used to analyze the epidemiological characteristics of the reinfection cases. Cox proportional hazards regression analysis to identify risk factors for the reinfection.

  Results  A total of 1 440 cases of reinfection of pathogens causing HFMD were reported in Jingzhou during this period, the reinfection rate was 1.99%, and the cumulative risk for the reinfection was 2.00%. A total of 1 394 cases were infected for two times (96.81%), 45 cases were infected for three times (3.12%), and 1 case was infected for four times (0.07%). There was no significant difference in the reinfection rate between boys (864 cases, 2.01%) and girls (576 cases, 1.97%) (P>0.05). The median of age of the cases infected for the 1^st–3^rd time was 1.75 years (1.17–2.67 years), 3.25 years (2.42–4.08 years), and 3.71 years (2.92–5.13 years), respectively. The cases of 1^st–3^rd infections were mainly children outside child care settings (78.96%), children in and outside child care settings (53.12% and 43.54%), and children in child care settings (56.52%) with number of severe cases 2, 3 and 0, respectively. The median time interval between two consecutive infections was 1.09 years (0.53–1.99 years), 1.06 years (0.61–1.54 years) and 0.60 years, respectively. After the first infection with enterovirus 71 (EV71), EV71, coxsackievirus 16 (Cox A16) and other types could be infected for the second time. Cox proportional hazards regression showed that the risk for the reinfection was higher in children aged <3 years compared with those aged ≥3 years hazard ratio (HR)=0.53, 95%CI: 0.45–0.63, in children outside child care settings compared with children in child care settings (HR=0.82, 95%CI: 0.70–0.97) and students (HR=0.14, 95%CI: 0.05–0.45), in children living in central urban area compared with those living in non-central urban area (HR=1.86, 95%CI: 1.67–2.08), in children infected with Cox A16 (HR=1.90, 95%CI: 1.51–2.39) and other types (HR=1.56, 95%CI: 1.31–1.85) for the first time compared with those infected with EV71 and in children infected with Cox A16 for the first time (HR=1.91, 95%CI: 1.25–2.93) compared with those infected with EV71, the differences were significant.

  Conclusion  There were obvious temporal and population heterogeneity in the reinfection of pathogens causing HFMD in Jingzhou, and intervention measures should be taken based on the findings in this study.