Estimating the extent of asymptomatic COVID-19 and its potential for community transmission: Systematic review and meta-analysis.
Estimating the extent of asymptomatic COVID-19 and its potential for community transmission: Systematic review and meta-analysis.
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DOI：
10.3138/jammi-2020-0030
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发表时间：
2020-12-01
期刊：
影响因子：
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通讯作者：
Glasziou, Paul
中科院分区：
文献类型：
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作者：
Byambasuren, Oyungerel;Cardona, Magnolia;Glasziou, Paul
背景：了解真正无症状冠状病毒病2019 （COVID-19）病例的流行情况对于制定缓解措施至关重要。我们的目的是综合所有关于无症状病例和传播率的现有研究。方法：我们检索了PubMed、Embase、Cochrane COVID-19试验和欧洲PMC中关于无症状患病率的初步研究，其中：(1)样本框架包括高危人群；(2)随访足以识别症状前病例。荟萃分析采用固定效应和随机效应模型。我们通过结合流行病学和诊断准确性研究的偏倚风险工具的问题来评估偏倚风险。结果：我们筛选了2454篇文章，包括来自7个国家的13项低风险偏倚研究，测试了21708名高危人群，其中663人阳性，111人无症状。所有研究的诊断均通过实时逆转录-聚合酶链反应试验得到证实。无症状比例从4%到41%不等。荟萃分析（固定效应）发现，总体而言，无症状病例的比例为17% (95% CI 14%至20%)，老年护理组（20%；95% CI 14%至27%）高于非老年护理组（16%；95% CI 13%至20%）。无症状传播的相对危险度（RR）比有症状传播的相对危险度（RR）低42%（合并RR 0.58; 95% CI 0.34 ~ 0.99, p = 0.047）。结论：我们对COVID-19无症状病例流行率和无症状传播率的六分之一的估计低于许多广为宣传的研究，但仍足以引起政策关注。迫切需要进一步强有力的流行病学证据，包括在儿童等亚人群中，以更好地了解无症状病例如何导致大流行。
Background: Knowing the prevalence of true asymptomatic coronavirus disease 2019 (COVID-19) cases is critical for designing mitigation measures against the pandemic. We aimed to synthesize all available research on asymptomatic cases and transmission rates.Methods: We searched PubMed, Embase, Cochrane COVID-19 trials, and Europe PMC for primary studies on asymptomatic prevalence in which (1) the sample frame includes at-risk populations and (2) follow-up was sufficient to identify pre-symptomatic cases. Meta-analysis used fixed-effects and random-effects models. We assessed risk of bias by combination of questions adapted from risk of bias tools for prevalence and diagnostic accuracy studies.Results: We screened 2,454 articles and included 13 low risk-of-bias studies from seven countries that tested 21,708 at-risk people, of which 663 were positive and 111 asymptomatic. Diagnosis in all studies was confirmed using a real-time reverse transcriptase-polymerase chain reaction test. The asymptomatic proportion ranged from 4% to 41%. Meta-analysis (fixed effects) found that the proportion of asymptomatic cases was 17% (95% CI 14% to 20%) overall and higher in aged care (20%; 95% CI 14% to 27%) than in non-aged care (16%; 95% CI 13% to 20%). The relative risk (RR) of asymptomatic transmission was 42% lower than that for symptomatic transmission (combined RR 0.58; 95% CI 0.34 to 0.99, p = 0.047).Conclusions: Our one-in-six estimate of the prevalence of asymptomatic COVID-19 cases and asymptomatic transmission rates is lower than those of many highly publicized studies but still sufficient to warrant policy attention. Further robust epidemiological evidence is urgently needed, including in subpopulations such as children, to better understand how asymptomatic cases contribute to the pandemic.