Hand, foot and mouth disease (HFMD) has high prevalence around the world, with serious consequences for children. Due to the long survival period of HFMD virus in ambient air, air pollutants may play a critical role in HFMD epidemics. We collected data on daily cases of HFMD among children aged 0–14 years in Ningbo City between 2014 and 2016. Distributed lag nonlinear models were used to assess the effects of particulate matter (PM2.5), sulphur dioxide (SO2), nitrogen dioxide (NO2) and ozone (O3) on the daily incidence of HFMD among children, with analyses stratified by gender and age. Compared with moderate levels of air pollution, high SO2 levels had a relative risk (RR) of 2.32 (95% CI 1.42–3.79) and high NO2 levels had a RR of 2.01 (95% CI 1.22–3.31). The RR of O3 was 2.12 (95% CI 1.47–3.05) and that of PM2.5 was 0.77 (95% CI 0.64–0.92) at moderate levels of air pollution. Specifically, high levels of SO2 and NO2 had RRs of 2.39 (95% CI 1.44–3.96) and 2.02 (95% CI 1.21–3.39), respectively, among 0–4-year-old children, while high O3 had an RR of 2.31 (95% CI 1.09–4.89) among 5–14-year-old children. Our findings suggest significant associations of high SO2 and NO2 levels and moderate O3 levels in HFMD epidemics, and also indicate that air pollution causes lagged effects on HFMD epidemics. Our study provides practical and useful data for targeted prevention and control of HMFD based on environmental evidence.

Febrile seizure (FS) in children is a common complication of infections with respiratory viruses and hand, foot and mouth disease (HFMD). We conducted a retrospective ecological time-series analysis to determine the temporal relationship between hospital attendances for FS and HFMD or respiratory virus infections. Epilepsy attendance was used as a control. Data from 2004 to 2012 FS and epilepsy hospital attendance, HFMD notifications to the Ministry of Health and from laboratory-confirmed viral respiratory infections among KK Women's and Children's Hospital inpatients were used. A multivariate linear regression analysis was conducted to evaluate the relationship between FS and the virus time series. Relative risks of FS by age were calculated using Bayesian statistical methods. Paediatric accident and emergency (A&E) attendances for FS were found to be associated with influenza A (extra 0.47 FS per influenza A case), B (extra 0.32 per influenza B case) and parainfluenza 3 (extra 0.35 per parainfluenza type 3 case). However, other viruses were not significantly associated with FS. None of the viruses were associated with epileptic seizure attendance. Influenza A, B and parainfluenza 3 viruses contributed to the burden of FS resulting in A&E attendance. Children at risk of FS should be advised to receive seasonal influenza vaccination.

Hand-foot-mouth disease (HFMD) is an acute infectious disease caused by serotypes of the enterovirus (EV) family. HFMD reinfection occurs commonly in lack of cross-protection between different EV serotypes. In this study, we investigated the hazards of HFMD reinfection using Cox-proportional hazard model. Retrospective data of 95 209 HFMD cases in Wuhan during 2008–2015 was used. Kaplan–Meier survival methods and Cox-proportional hazard model were used to estimate the hazard probabilities. Of the all HFMD cases, about 2% experienced reinfection (1842/95 209). Kaplan–Meier curves revealed the reinfection risk sharply increased before 40 months from first infection. Higher hazards of reinfection were detected among those who were males, aged 3 years and below, scattered children, belonging to urban areas and first infected with coxsackievirus (CV)-A16 compared with their respective counterparts. Cox-proportional hazard model suggested that gender, age, group, living area and serotypes of first infection had significant effect on reinfection even after adjusting for potential confounding effects of other selected factors considered in the study. These results indicate that boys aged 3 years and below, especially those living in urban areas and first infected with CV-A16 are more prone to reinfection. Interventions should be imposed on these high-risk populations.

Hand, foot, and mouth disease (HFMD) is highly prevalent in China, and more efficient methods of epidemic detection and early warning need to be developed to augment traditional surveillance systems. In this paper, a method that uses Baidu search queries to track and predict HFMD epidemics is presented, and the outbreaks of HFMD in China during the 60-month period from January 2011 to December 2015 are predicted. The Pearson correlation coefficient (R) of the predictive model and the mean absolute percentage errors between observed HFMD case counts and the predicted number show that our predictive model gives excellent fit to the data. This implies that Baidu search queries can be used in China to track and reliably predict HFMD epidemics, and can serve as a supplement to official systems for HFMD epidemic surveillance.

Hand, foot and mouth disease (HFMD) associated with enterovirus 71 (EV71) is a growing public health concern. This study aimed to estimate the case-fatality of HFMD associated with EV71 on the basis of a meta-analysis. We searched PubMed, Cochrane, Web of Science, Elsevier, CNKI, Wanfang, and VIP databases. Two authors independently selected relevant studies. The pooled estimate of case-fatality was calculated using a random-effects model. Potential sources of heterogeneity were explored using subgroup analysis, sensitivity analysis and meta-regression. We identified 14 eligible studies with a total population of 112 546. The random-effects pooled case-fatality was 1·7% (95% confidence interval 1·2–2·4). The funnel plot was asymmetrical. The estimate of case-fatality was highest in mainland China (1·8%). Removal of eight local Chinese studies decreased the original estimate. The pooled case-fatality in the period of 1998–2007 (1·5%) was lower than that in the period 2008–2012 (1·8%). Control measures for HFMD associated with EV71 are essential because of the increased case-fatality over time, especially in East Asia.