SARS-CoV-2 Transmission From People Without COVID-19 Symptoms.
SARS-CoV-2 Transmission From People Without COVID-19 Symptoms.
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DOI：
10.1001/jamanetworkopen.2020.35057
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发表时间：
2021-01-04
影响因子：
13.8
通讯作者：
Butler JC
中科院分区：
文献类型：
--
作者：
Johansson MA;Quandelacy TM;Kada S;Prasad PV;Steele M;Brooks JT;Slayton RB;Biggerstaff M;Butler JC
2019 年冠状病毒病 (COVID-19) 传播中，有多少比例与无症状人群传播严重急性呼吸综合征冠状病毒 2 (SARS-CoV-2) 有关？在这个决策分析模型中，评估了感染期的多种情况以及从未出现过 COVID-19 症状的个体的传播比例，据估计，无症状个体的传播占所有传播的一半以上。这项研究的结果表明，仅识别和隔离有症状的 COVID-19 患者并不能控制 SARS-CoV-2 的持续传播。该决策分析模型评估了社区中可能由无症状人群传播的严重急性呼吸综合征冠状病毒 2 (SARS-CoV-2) 传播的比例。严重急性呼吸综合征冠状病毒 2 (SARS-CoV-2) 是 2019 年冠状病毒病 (COVID-19) 的病因，很容易在人与人之间传播。对 COVID-19 的最佳控制取决于将资源和健康信息用于最有可能防止传播的缓解工作，但此类措施的相对重要性一直存在争议。评估社区中 SARS-CoV-2 传播可能由无症状人群传播的比例。该决策分析模型评估了一系列场景中无症状、无症状和有症状个体的相对传播量，其中从未出现症状（即保持无症状）和感染期的人的传播比例根据已发布的最佳估计而变化。对于所有估计，均使用荟萃分析数据将潜伏期设定为中位数 5 天。传染期持续时间维持在10天，传染性峰值在3至7天之间变化（相对于中位潜伏期为-2天和+2天）。 SARS-CoV-2 的总体比例在 0% 到 70% 之间变化，以评估各种可能的比例。 SARS-CoV-2 从症状前、无症状和有症状个体的传播水平。该模型的基线假设是，传染性高峰出现在症状出现的中间时间，并且 30% 的感染者从未出现症状，75% 的感染者与出现症状的人具有相同的传染性。综合起来，这些基线假设意味着从未出现症状的感染者可能约占所有传播的 24%。在这个基本案例中，所有传播的 59% 来自无症状传播，其中 35% 来自症状前个体，24% 来自从未出现症状的个体。根据这些假设的广泛值，估计至少 50% 的新 SARS-CoV-2 感染源自接触感染但无症状的个体。在这个关于 COVID-19 无症状个体比例和感染期的多种场景的决策分析模型中，无症状个体的传播估计占所有传播的一半以上。除了识别和隔离有症状的 COVID-19 患者外，有效控制传播还需要降低无症状感染者的传播风险。这些发现表明，在安全有效的疫苗问世并得到广泛使用之前，戴口罩、保持手部卫生、保持社交距离以及对未患病者进行战略性检测等措施将是减缓 COVID-19 传播的基础。
What proportion of coronavirus disease 2019 (COVID-19) spread is associated with transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from persons with no symptoms? In this decision analytical model assessing multiple scenarios for the infectious period and the proportion of transmission from individuals who never have COVID-19 symptoms, transmission from asymptomatic individuals was estimated to account for more than half of all transmission. The findings of this study suggest that the identification and isolation of persons with symptomatic COVID-19 alone will not control the ongoing spread of SARS-CoV-2. This decision analytical model assesses the proportion of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmissions in the community that likely occur from persons without symptoms. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiology of coronavirus disease 2019 (COVID-19), is readily transmitted person to person. Optimal control of COVID-19 depends on directing resources and health messaging to mitigation efforts that are most likely to prevent transmission, but the relative importance of such measures has been disputed. To assess the proportion of SARS-CoV-2 transmissions in the community that likely occur from persons without symptoms. This decision analytical model assessed the relative amount of transmission from presymptomatic, never symptomatic, and symptomatic individuals across a range of scenarios in which the proportion of transmission from people who never develop symptoms (ie, remain asymptomatic) and the infectious period were varied according to published best estimates. For all estimates, data from a meta-analysis was used to set the incubation period at a median of 5 days. The infectious period duration was maintained at 10 days, and peak infectiousness was varied between 3 and 7 days (−2 and +2 days relative to the median incubation period). The overall proportion of SARS-CoV-2 was varied between 0% and 70% to assess a wide range of possible proportions. Level of transmission of SARS-CoV-2 from presymptomatic, never symptomatic, and symptomatic individuals. The baseline assumptions for the model were that peak infectiousness occurred at the median of symptom onset and that 30% of individuals with infection never develop symptoms and are 75% as infectious as those who do develop symptoms. Combined, these baseline assumptions imply that persons with infection who never develop symptoms may account for approximately 24% of all transmission. In this base case, 59% of all transmission came from asymptomatic transmission, comprising 35% from presymptomatic individuals and 24% from individuals who never develop symptoms. Under a broad range of values for each of these assumptions, at least 50% of new SARS-CoV-2 infections was estimated to have originated from exposure to individuals with infection but without symptoms. In this decision analytical model of multiple scenarios of proportions of asymptomatic individuals with COVID-19 and infectious periods, transmission from asymptomatic individuals was estimated to account for more than half of all transmissions. In addition to identification and isolation of persons with symptomatic COVID-19, effective control of spread will require reducing the risk of transmission from people with infection who do not have symptoms. These findings suggest that measures such as wearing masks, hand hygiene, social distancing, and strategic testing of people who are not ill will be foundational to slowing the spread of COVID-19 until safe and effective vaccines are available and widely used.