Assessing the vaccine effectiveness for hand, foot, and mouth disease in Guangzhou, China: a time-series analysis

Objective: Hand, foot, and mouth disease (HFMD) is an important public health issue in China. Although efficacy has been demonstrated by randomized controlled trials, the evidence for effectiveness of the monovalent Enterovirus 71 (EV71) vaccine against HFMD remains unknown. This study aimed to assess the vaccine effectiveness for HFMD in Guangzhou, China. Methods: Routinely collected vaccination and HFMD surveillance data were captured from the China Information System for Disease Control and Prevention. We estimated the EV71 vaccine effectiveness using spatial ecologic and time-series analysis approaches. Results: A total of 174,002 HFMD cases under 5 years of age were reported to the Guangzhou, China surveillance system from January 2016 to December 2018. A total of 408,664 children completed a two-dose EV71 vaccination series. In an ecologic analysis, a two-dose EV71 vaccination rate above the median conferred lower HFMD risk relative to a vaccination rate below the median (ratio ratio = 0.955, 95% confidence interval (CI): 0.949, 0.962; P