Spatial-temporal-demographic and virological changes of hand, foot and mouth disease incidence after vaccination in a vulnerable region of China.

BACKGROUND: The enterovirus 71 (EV-A71) vaccine has been used in Hefei for several years, and the epidemiological significance of vaccination in this area is unclear. We aims to explore the spatial-temporal-demographic and virological changes of hand, foot and mouth disease (HFMD) after vaccination in China. METHODS: The data for HFMD from 2012 to 2020 were downloaded with the help of HFMD reporting system of Hefei Center for Disease Control and Prevention and combined with the EV-A71 vaccination status in Hefei. The study defined the period between 2012 to 2016 as the pre-vaccination period and explored the effect of vaccination on the incidence of HFMD by comparing the changes of HFMD before and after vaccination in terms of spatial, temporal, demographic and virological aspects. RESULTS: During the study period, a higher incidence occurred in urban area and the random distribution changed to a slight cluster after vaccination. HFMD incidence had inconsistent seasonality over years, with one or two incidence peaks in varying years. The morbidity decreased from 215.22/105 in 2012-2016 to 179.81/105 in 2017-2020 (p < 0.001). Boys, 0-4 years old children and Scattered children were more susceptible to HFMD compared with the others, the proportions decreased after vaccination except in Scattered children. The main pathogenic enterovirus gradually changed from EV-A71 to Other Enteroviruses, especially coxsackieviruses A6 (CV-A6) after the implementation of EV-A71 vaccination. CONCLUSIONS: The EV-A71 vaccine was effective in reducing the incidence of HFMD and changing the spatial, temporal, demographic, and virological characteristic. These changes should be considered during the vaccination implementation to further reduce the disease burden of HFMD.

[Study on the score criteria of severe hand, foot and mouth disease cases].

OBJECTIVE: To explore the score criteria of severe hand, foot and mouth disease (HFMD) cases and to provide evidence for unified criteria and treatment on severe HFMD cases. METHODS: All severe cases and partial mild cases reported by two designated hospitals of HFMD in Fuyang during March to June, 2008 were scored by the methods of criteria constructed in advance. ROC curve was adopted to evaluate the score criteria and the gold standard was defined according to ICU, intubation and clinical outcomes, etc. Sensitivity, specificity and Youden's index were used to determine the division scores on critical, severe and mild cases. RESULTS: 97% of the cases (34 cases) were scored less than 6 points. 88% of cases (24 cases) who were intubated or mechanical ventilated had the scores of 6 points or higher. 79% of deaths (11 cases) were scored 10 points or higher. The area of receiver operation characteristic (ROC) curve was 0.90 (95%CI: 0.83 - 0.98) between severe and mild cases and the area of ROC curve was 0.95 (95%CI: 0.92 - 0.98) between critical and severe, mild cases. When comprehensively considering the sensitivity and specificity, severe cases were best judged when score was 4 points (sensitivity, specificity and Youden's index were 0.94, 0.68 and 0.62 respectively). When score was 6 points, critical cases were judged very well (sensitivity, specificity and Youden's index were 0.92, 0.84 and 0.76 respectively). CONCLUSION: Score criteria could be quantified to determine the degree of seriousness and with high-value for diagnosis on HFMD.