Nanjing Municipal Center for Disease Control and Prevention, Nanjing, China.
Chinese Field Epidemiology Training Program (CFETP), Beijing, China.
Clin Infect Dis. 2021 Nov 2;73(9):e2552-e2559. doi: 10.1093/cid/ciaa1853.
Enterovirus 71 (EV-A71), coxsackievirus A16 (CV-A16), and coxsackievirus A6 (CV-A6) are common serotypes causing hand, foot, and mouth disease (HFMD). Analyses on the basic reproduction number (R0) of common pathogens causing HFMD are limited and there are no related studies using field data from outbreaks in mainland China.
We estimated the pathogen-specific basic reproduction number based on laboratory-confirmed HFMD outbreaks (clusters of ≥10 HFMD cases) reported to the national surveillance system between 2011 and 2018. The reproduction numbers were calculated using a mathematical model and the cumulative cases during the initial growth periods.
This study included 539 outbreaks, of which 198 were caused by EV-A71, 316 by CV-A16, and 25 by CV-A6. All 10 417 cases involved were children. Assuming the outbreaks occurred in closed systems and the incubation period is 5 days, the median (interquartile range [IQR]) R0 estimates of EV-A71, CV-A16, and CV-A6 were 5.06 (2.81, 10.20), 4.84 (3.00, 9.00), and 5.94 (3.27, 10.00). After adjusting for seroprevalences, the R0 (IQR) estimates for EV-A71, CV-A16 (optimistic and conservative scenarios), and CV-A6 were 12.60 (7.35, 25.40), 9.29 (6.01, 19.20), 15.50 (9.77, 30.40), and 25.80 (14.20, 43.50), respectively. We did not observe changes in the R0 of EV-A71 after vaccine licensure (P = .67).
HFMD is highly transmissible when caused by the 3 most common serotypes. In mainland China, it primarily affects young children. Although a vaccine became available in 2016, we have not yet observed any related changes in the disease dynamics.
肠道病毒 71 型（EV-A71）、柯萨奇病毒 A16 型（CV-A16）和柯萨奇病毒 A6 型（CV-A6）是引起手足口病（HFMD）的常见血清型。对手足口病常见病原体基本繁殖数（R0）的分析有限，并且没有使用中国大陆暴发的现场数据进行相关研究。
我们根据 2011 年至 2018 年全国监测系统报告的实验室确诊手足口病暴发（≥10 例手足口病病例的聚集），估计了病原体特异性基本繁殖数。繁殖数是使用数学模型和初始增长期的累积病例数计算的。
本研究共包括 539 起暴发，其中 198 起因 EV-A71 引起，316 起因 CV-A16 引起，25 起因 CV-A6 引起。所有 10417 例病例均为儿童。假设暴发发生在封闭系统中，潜伏期为 5 天，则 EV-A71、CV-A16 和 CV-A6 的中位（四分位距 [IQR]）R0 估计值分别为 5.06（2.81，10.20）、4.84（3.00，9.00）和 5.94（3.27，10.00）。调整血清流行率后，EV-A71、CV-A16（乐观和保守情景）和 CV-A6 的 R0（IQR）估计值分别为 12.60（7.35，25.40）、9.29（6.01，19.20）、15.50（9.77，30.40）和 25.80（14.20，43.50）。我们没有观察到疫苗许可后 EV-A71 的 R0 发生变化（P=.67）。
由这 3 种最常见血清型引起的手足口病具有高度传染性。在中国内地，它主要影响幼儿。尽管 2016 年出现了一种疫苗，但我们尚未观察到手足口病动态的任何相关变化。
