TY - JOUR T1 - Role of presymptomatic transmission of COVID-19: evidence from Beijing, China. AU - Zhang,Yi, AU - Muscatello,David, AU - Tian,Yi, AU - Chen,Yanwei, AU - Li,Shuang, AU - Duan,Wei, AU - Ma,Chunna, AU - Sun,Ying, AU - Wu,Shuangsheng, AU - Ge,Lin, AU - Yang,Peng, AU - Jia,Lei, AU - Wang,Quanyi, AU - MacIntyre,Chandini Raina, Y1 - 2020/08/27/ PY - 2020/05/23/received PY - 2020/07/21/revised PY - 2020/07/28/accepted PY - 2020/8/29/pubmed PY - 2020/12/29/medline PY - 2020/8/29/entrez KW - Communicable diseases KW - control of diseases KW - public health policy SP - 84 EP - 87 JF - Journal of epidemiology and community health JO - J Epidemiol Community Health VL - 75 IS - 1 N2 - BACKGROUND: The presymptomatic transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been documented in limited clusters, and it is predicted through modelling. However, there is a lack of evidence from observations with a large sample size. METHODS: We used data from meticulous contact tracing of people exposed to cases of SARS-CoV-2 to estimate the proportion of cases that result from the presymptomatic transmission of the virus in Beijing during January 2020 and February 2020. RESULTS: The results showed that presymptomatic transmission occurred in at least 15% of 100 secondary COVID-19 cases. The earliest presymptomatic contact event occurred 5 days prior to the index case's onset of symptoms, and this occurred in two clusters. CONCLUSIONS: The finding suggested that the contact tracing period should be earlier and highlighted the importance of preventing transmission opportunities well before the onset of symptoms. SN - 1470-2738 UR - https://www.unboundmedicine.com/medline/citation/32855261/Role_of_presymptomatic_transmission_of_COVID_19:_evidence_from_Beijing_China_ DB - PRIME DP - Unbound Medicine ER -