奥密克戎 BA.2 流行期间抑制控制措施下的特定年龄传播动力学。
Age-specific transmission dynamics under suppression control measures during SARS-CoV-2 Omicron BA.2 epidemic.
机构信息
Shanghai Institute of Infectious Disease and Biosecurity, School of Public Health, Fudan University, 138 Yi Xue Yuan Road, Shanghai, 200032, China.
School of Epidemiology and Public Health, University of Ottawa, Ottawa, K1G5Z3, Canada.
出版信息
BMC Public Health. 2023 Apr 22;23(1):743. doi: 10.1186/s12889-023-15596-w.
BACKGROUND
From March to June 2022, an Omicron BA.2 epidemic occurred in Shanghai. We aimed to better understand the transmission dynamics and identify age-specific transmission characteristics for the epidemic.
METHODS
Data on COVID-19 cases were collected from the Shanghai Municipal Health Commission during the period from 20th February to 1st June. The effective reproductive number (R) and transmission distance between cases were calculated. An age-structured SEIR model with social contact patterns was developed to reconstruct the transmission dynamics and evaluate age-specific transmission characteristics. Least square method was used to calibrate the model. Basic reproduction number (R) was estimated with next generation matrix.
RESULTS
R of Omicron variant was 7.9 (95% CI: 7.4 to 8.4). With strict interventions, R had dropped quickly from 3.6 (95% CI: 2.7 to 4.7) on 4th March to below 1 on 18th April. The mean transmission distance of the Omicron epidemic in Shanghai was 13.4 km (95% CI: 11.1 to 15.8 km), which was threefold longer compared with that of epidemic caused by the wild-type virus in Wuhan, China. The model estimated that there would have been a total 870,845 (95% CI: 815,400 to 926,289) cases for the epidemic from 20th February to 15th June, and 27.7% (95% CI: 24.4% to 30.9%) cases would have been unascertained. People aged 50-59 years had the highest transmission risk 0.216 (95% CI: 0.210 to 0.222), and the highest secondary attack rate (47.62%, 95% CI: 38.71% to 56.53%).
CONCLUSIONS
The Omicron variant spread more quickly and widely than other variants and resulted in about one third cases unascertained for the recent outbreak in Shanghai. Prioritizing isolation and screening of people aged 40-59 might suppress the epidemic more effectively. Routine surveillance among people aged 40-59 years could also provide insight into the stage of the epidemic and the timely detection of new variants.
TRIAL REGISTRATION
We did not involve clinical trial.
背景
2022 年 3 月至 6 月，上海发生了一起由奥密克戎 BA.2 引起的疫情。本研究旨在更好地了解其传播动力学，并确定特定年龄的传播特征。
方法
我们收集了 2 月 20 日至 6 月 1 日期间上海市卫生健康委员会的 COVID-19 病例数据。计算了有效繁殖数（R）和病例之间的传播距离。我们建立了一个具有社会接触模式的年龄结构 SEIR 模型，以重建传播动力学并评估特定年龄的传播特征。使用最小二乘法对模型进行校准。使用下一代矩阵估计基本繁殖数（R）。
结果
奥密克戎变异株的 R 为 7.9（95%CI：7.4-8.4）。在严格的干预措施下，R 值迅速从 3 月 4 日的 3.6（95%CI：2.7-4.7）下降到 4 月 18 日的 1 以下。上海奥密克戎疫情的平均传播距离为 13.4 公里（95%CI：11.1-15.8 公里），是中国武汉野生型病毒疫情的三倍。模型估计，从 2 月 20 日至 6 月 15 日，该疫情将总共出现 870845 例（95%CI：815400-926289），27.7%（95%CI：24.4%-30.9%）的病例无法确定。50-59 岁人群的传播风险最高，为 0.216（95%CI：0.210-0.222），二次感染率（47.62%，95%CI：38.71%-56.53%）最高。
结论
奥密克戎变异株的传播速度和范围比其他变异株更快更广，导致上海最近的疫情约有三分之一的病例无法确定。优先对 40-59 岁人群进行隔离和筛查可能会更有效地抑制疫情。对 40-59 岁人群进行常规监测也可以深入了解疫情阶段和及时发现新的变异株。
研究注册
我们没有涉及临床试验。
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