Since the emergence of coronavirus disease 2019 (COVID-19), unprecedented movement restrictions and social distancing measures have been implemented worldwide. The socioeconomic repercussions have fueled calls to lift these measures. In the absence of population-wide restrictions, isolation of infected individuals is key to curtailing transmission. However, the effectiveness of symptom-based isolation in preventing a resurgence depends on the extent of presymptomatic and asymptomatic transmission. We evaluate the contribution of presymptomatic and asymptomatic transmission based on recent individual-level data regarding infectiousness prior to symptom onset and the asymptomatic proportion among all infections. We found that the majority of incidences may be attributable to silent transmission from a combination of the presymptomatic stage and asymptomatic infections. Consequently, even if all symptomatic cases are isolated, a vast outbreak may nonetheless unfold. We further quantified the effect of isolating silent infections in addition to symptomatic cases, finding that over one-third of silent infections must be isolated to suppress a future outbreak below 1% of the population. Our results indicate that symptom-based isolation must be supplemented by rapid contact tracing and testing that identifies asymptomatic and presymptomatic cases, in order to safely lift current restrictions and minimize the risk of resurgence.

自2019年冠状病毒疾病（COVID-19）出现以来，全球范围内已实施了前所未有的行动限制和社会疏远措施。社会经济影响引发了取消这些措施的呼吁。在没有整个人群的限制的情况下，隔离感染个体是减少传播的关键。但是，基于症状的隔离在防止复发中的有效性取决于症状前和无症状传播的程度。我们根据有关症状发作之前的传染性和所有感染中无症状比例的最新个体水平数据，评估有症状和无症状传播的贡献。我们发现，大多数发病率可能归因于症状前阶段和无症状感染的无声传播。因此，即使所有有症状的病例都被隔离了，仍然可能爆发大规模的疫情。我们进一步量化了除了有症状的病例之外，隔离无声感染的效果，发现必须隔离超过三分之一的无声感染，才能将未来的暴发抑制在总人口的1％以下。我们的结果表明，基于症状的隔离必须辅以快速的接触者追踪和测试，以识别无症状和症状前的情况，以安全地解除电流限制并最大程度地降低复发风险。我们进一步量化了除了有症状的病例之外，隔离无声感染的效果，发现必须隔离超过三分之一的无声感染，才能将未来的暴发抑制在总人口的1％以下。我们的结果表明，基于症状的隔离必须辅以快速的接触者追踪和测试，以识别无症状和症状前的情况，以安全地解除电流限制并最大程度地降低复发风险。我们进一步量化了除了有症状的病例之外，隔离无声感染的效果，发现必须隔离超过三分之一的无声感染，才能将未来的暴发抑制在总人口的1％以下。我们的结果表明，基于症状的隔离必须辅以快速的接触者追踪和测试，以识别无症状和症状前的情况，以安全地解除电流限制并最大程度地降低复发风险。