Age-dependent effects in the transmission and control of COVID-19 epidemics
Age-dependent effects in the transmission and control of COVID-19 epidemics
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DOI：
10.1038/s41591-020-0962-9
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发表时间：
2020-06-16
期刊：
影响因子：
82.9
通讯作者：
Eggo, Rosalind M.
中科院分区：
文献类型：
--
作者：
Davies, Nicholas G.;Klepac, Petra;Eggo, Rosalind M.
一项新的流行病学研究显示，在20岁以下的人群中，对SARS-CoV-2的易感性降低，出现严重症状的风险降低，这表明儿童对COVID-19传播的贡献有限。新冠肺炎疫情显示，儿童中的病例比例明显较低(1-4)。观察到的病例中的年龄差异可以解释为儿童对感染的易感性较低，或出现临床症状的倾向较低，或者两者兼而有之。我们通过将年龄结构的数学模型与中国、意大利、日本、新加坡、加拿大和韩国的疫情数据进行拟合来评估这些可能性。我们估计，20岁以下的人对感染的易感性大约是20岁以上成年人的一半，10至19岁的人中有21%(95%可信区间：12-31%)出现临床症状，70岁以上的人中有69%(57-82%)出现临床症状。因此，我们发现，针对儿童的干预措施可能对减少SARS-CoV-2传播的影响相对较小，特别是在亚临床感染的传播率较低的情况下。由于不同环境下的人口统计学差异，我们对年龄特定的临床分数和易感性的估计对新冠肺炎的预期全球负担有影响。在人口结构较年轻的国家--例如许多低收入国家--临床病例的人均预期发病率将低于人口结构较老的国家，尽管低收入国家的并存也可能影响疾病的严重程度。如果没有有效的控制措施，人口相对老龄化的地区可能会出现不成比例的更多新冠肺炎病例，特别是在疫情肆虐的后期。
A new epidemiological study shows reduced susceptibility to SARS-CoV-2 and decreased risk of developing severe symptoms in people aged younger than 20 years, suggesting that children have limited contribution to spread of COVID-19.The COVID-19 pandemic has shown a markedly low proportion of cases among children(1-4). Age disparities in observed cases could be explained by children having lower susceptibility to infection, lower propensity to show clinical symptoms or both. We evaluate these possibilities by fitting an age-structured mathematical model to epidemic data from China, Italy, Japan, Singapore, Canada and South Korea. We estimate that susceptibility to infection in individuals under 20 years of age is approximately half that of adults aged over 20 years, and that clinical symptoms manifest in 21% (95% credible interval: 12-31%) of infections in 10- to 19-year-olds, rising to 69% (57-82%) of infections in people aged over 70 years. Accordingly, we find that interventions aimed at children might have a relatively small impact on reducing SARS-CoV-2 transmission, particularly if the transmissibility of subclinical infections is low. Our age-specific clinical fraction and susceptibility estimates have implications for the expected global burden of COVID-19, as a result of demographic differences across settings. In countries with younger population structures-such as many low-income countries-the expected per capita incidence of clinical cases would be lower than in countries with older population structures, although it is likely that comorbidities in low-income countries will also influence disease severity. Without effective control measures, regions with relatively older populations could see disproportionally more cases of COVID-19, particularly in the later stages of an unmitigated epidemic.