Estimation of country-level basic reproductive ratios for novel Coronavirus (SARS-CoV-2/COVID-19) using synthetic contact matrices
Estimation of country-level basic reproductive ratios for novel Coronavirus (SARS-CoV-2/COVID-19) using synthetic contact matrices
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DOI：
10.1371/journal.pcbi.1008031
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发表时间：
2020-07-01
影响因子：
4.3
通讯作者：
Keeling, Matt J.
中科院分区：
文献类型：
--
作者：
Hilton, Joe;Keeling, Matt J.
由SARSCoV-2病毒引起的2019-2020年非典型肺炎（COVID-19）大流行已在全球蔓延，并有可能在每个国家感染大量人群。估计具体国家的基本生殖比率是公共卫生规划的重要第一步。基本生殖比率（R-0）由病原体的性质和疾病可通过的人际接触网络决定，而人际接触网络本身又取决于人口年龄结构和家庭组成。在这里，我们引入了一个传播模型，该模型结合了年龄分层接触频率、年龄依赖性易感性、临床症状概率和无症状（或轻度）病例传播，我们使用该模型来估计152个国家的COVID-19国别基本生殖比。利用来自中国的早期疫情数据和合成接触矩阵，我们估计了年龄分层的传播结构，然后可以将其外推到其他151个国家，这些国家也存在合成接触矩阵。这定义了一套具体国家的传播结构，我们可以据此计算每个国家的基本生殖比率。我们预测的R-0对无症状病例的传播强度极为敏感；在无症状传播较低的情况下，预计东欧和日本的值最高，非洲、中美洲和西南亚的值最低。这种模式主要是由每个国家儿童与老年人的比例以及观察到的老年人临床病例的倾向所驱动的。如果无症状病例的传播与发现病例相当，则模式相反。我们的研究结果表明，年龄特异性异质性在接触结构之外对COVID-19传播的重要性。这些异质性使得COVID-19能够在人口老龄化的国家特别迅速地传播，并且可能需要采取强化控制措施来阻止其在这些国家的进展。
The 2019-2020 pandemic of atypical pneumonia (COVID-19) caused by the virus SARSCoV-2 has spread globally and has the potential to infect large numbers of people in every country. Estimating the country-specific basic reproductive ratio is a vital first step in public-health planning. The basic reproductive ratio (R-0) is determined by both the nature of pathogen and the network of human contacts through which the disease can spread, which is itself dependent on population age structure and household composition. Here we introduce a transmission model combining age-stratified contact frequencies with age-dependent susceptibility, probability of clinical symptoms, and transmission from asymptomatic (or mild) cases, which we use to estimate the country-specific basic reproductive ratio of COVID-19 for 152 countries. Using early outbreak data from China and a synthetic contact matrix, we estimate an age-stratified transmission structure which can then be extrapolated to 151 other countries for which synthetic contact matrices also exist. This defines a set of country-specific transmission structures from which we can calculate the basic reproductive ratio for each country. Our predicted R-0 is critically sensitive to the intensity of transmission from asymptomatic cases; with low asymptomatic transmission the highest values are predicted across Eastern Europe and Japan and the lowest across Africa, Central America and South-Western Asia. This pattern is largely driven by the ratio of children to older adults in each country and the observed propensity of clinical cases in the elderly. If asymptomatic cases have comparable transmission to detected cases, the pattern is reversed. Our results demonstrate the importance of age-specific heterogeneities going beyond contact structure to the spread of COVID-19. These heterogeneities give COVID-19 the capacity to spread particularly quickly in countries with older populations, and that intensive control measures are likely to be necessary to impede its progress in these countries.