University of British Columbia, Vancouver, Canada.
Simon Fraser University, Burnaby, Canada.
Elife. 2020 Jun 22;9:e57149. doi: 10.7554/eLife.57149.
We collated contact tracing data from COVID-19 clusters in Singapore and Tianjin, China and estimated the extent of pre-symptomatic transmission by estimating incubation periods and serial intervals. The mean incubation periods accounting for intermediate cases were 4.91 days (95%CI 4.35, 5.69) and 7.54 (95%CI 6.76, 8.56) days for Singapore and Tianjin, respectively. The mean serial interval was 4.17 (95%CI 2.44, 5.89) and 4.31 (95%CI 2.91, 5.72) days (Singapore, Tianjin). The serial intervals are shorter than incubation periods, suggesting that pre-symptomatic transmission may occur in a large proportion of transmission events (0.4-0.5 in Singapore and 0.6-0.8 in Tianjin, in our analysis with intermediate cases, and more without intermediates). Given the evidence for pre-symptomatic transmission, it is vital that even individuals who appear healthy abide by public health measures to control COVID-19.
我们整理了新加坡和中国天津的 COVID-19 聚集性病例的接触者追踪数据，并通过估计潜伏期和序列间隔来估计无症状传播的程度。分别考虑中间病例时，新加坡和天津的平均潜伏期为 4.91 天（95%CI 4.35, 5.69）和 7.54 天（95%CI 6.76, 8.56）。平均序列间隔分别为 4.17 天（95%CI 2.44, 5.89）和 4.31 天（95%CI 2.91, 5.72）（新加坡，天津）。序列间隔短于潜伏期，这表明无症状传播可能发生在很大比例的传播事件中（在我们的分析中，考虑中间病例时，新加坡为 0.4-0.5，天津为 0.6-0.8，而没有中间病例时则更多）。鉴于存在无症状传播的证据，即使看起来健康的个体也必须遵守公共卫生措施来控制 COVID-19。
