Impact of the launch of EV71 vaccination on prevalence characteristics and pathogen spectrum of severe hand, foot and mouth disease in Henan province, 2014 – 2020: a register data analysis

Abstract

Objective To explore changes in prevalence characteristics and pathogen spectrum of severe hand, foot and mouth disease (HFMD) in Henan province before and after launching vaccination of enterovirus 71 (EV71) vaccine for developing strategies on HFMD prevention and control. MethodsThe data on all HFMD cases registered in Henan province from 2014 through 2020 were extracted from the Infectious Disease Report Information Management System of the Chinese Center for Disease Control and Prevention. Descriptive statistics was performed on the data to assess changes in constituent ratio of and distribution of pathogens detected in the severe HFMD cases before and after of the launch of EV71 vaccination from 2017 in the province. ResultsDuring 2014 to 2020, totally 13 535 severe HFMD cases were reported in the province, with a male-to-female ratio of 1.58:1 and the most (97.34%, 13 175) of the cases were children under the age of 5 years. A unimodal pattern throughout the year was observed in the incidence of severe HFMD, with the peak season mainly occurring from April to July and 75.53% (10 223) of the registered severe cases occurred during the season. The ratio of severe cases decreased significantly from 3.19% (10 948/343 585) for the period of 2014 – 2016 to 0.93% (2 587/278 075) for the period of 2017 – 2020 with the launch of EV71 vaccination (χ2 = 3672.874, P < 0.001). For the severe HFMD cases reported during 2017 – 2020, the proportion of the cases of one- and two-year-old decreased significantly from 47.23% to 42.83% (χ2 = 16.311, P1 < 0.001) and from 25.57% to 22.84% (χ2 = 8.255, P2 = 0.004); but the proportion of the cases occurred in preschool care facilities increased significantly from 9.13% to 16.24% (χ2 = 112.359, P < 0.001). Following the promotion of EV71 vaccination among the public, the detection rate of EV71 among the severe HFMD cases decreased from 65.14% to 29.63%, while that of other enteroviruses increased from 27.49% to 56.13%, indicating that other enteroviruses became dominant serotypes for pathogens of HFMD epidemic. ConclusionThe ratio of severe cases among registered HFMD cases had significantly decreased after the launch of the EV71 vaccination in Henan province and the dominant pathogen of HFMD changed from EV71 to other enteroviruses. The results suggest that EV71 vaccination ought to be promoted among key populations and in peak season to prevent severe HFMD epidemic.

Keywords

• hand, foot and mouth disease
• enterovirus 71 vaccine
• severe cases
• prevalence characteristics
• pathogen spectrum