Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI, 53706, USA.
Wildlife Analysis GmbH, Oetlisbergstrasse 38, 8053, Zurich, Switzerland.
Commun Biol. 2021 Jan 5;4(1):60. doi: 10.1038/s42003-020-01609-6.
The basic reproduction number, R, determines the rate of spread of a communicable disease and therefore gives fundamental information needed to plan public health interventions. Using mortality records, we estimated the rate of spread of COVID-19 among 160 counties and county-aggregates in the USA at the start of the epidemic. We show that most of the high among-county variance is explained by four factors (R = 0.70): the timing of outbreak, population size, population density, and spatial location. For predictions of future spread, population density and spatial location are important, and for the latter we show that SARS-CoV-2 strains containing the G614 mutation to the spike gene are associated with higher rates of spread. Finally, the high predictability of R allows extending estimates to all 3109 counties in the conterminous 48 states. The high variation of R argues for public health policies enacted at the county level for controlling COVID-19.
基本再生数 R 决定了传染病的传播速度，因此为规划公共卫生干预措施提供了基本信息。我们利用死亡率记录，在疫情开始时估计了美国 160 个县和县级行政区的 COVID-19 传播速度。结果表明，大部分县间差异可由四个因素解释（R=0.70）：暴发时间、人口规模、人口密度和空间位置。对于未来传播的预测，人口密度和空间位置很重要，而且我们还发现，含有刺突蛋白 G614 突变的 SARS-CoV-2 株与更高的传播速度有关。最后，R 的高可预测性允许将估计扩展到毗邻 48 个州的所有 3109 个县。R 的高度变化表明，需要在县一级制定公共卫生政策来控制 COVID-19。
