Phylogenomic tracing of asymptomatic transmission in a COVID-19 outbreak.

SARS-CoV-2 has caused over 100 million deaths and continues to spread rapidly around the world. Asymptomatic transmission of SARS-CoV-2 is the Achilles' heel of COVID-19 public health control measure. Phylogenomic data on SARS-CoV-2 could provide more direct information about asymptomatic transmission. In the present study, using a novel MINERVA sequencing technology, we traced asymptomatic transmission of COVID-19 patients in Beijing, China. 178 close-contacts were quarantined, and 14 COVID-19 patients were laboratory-confirmed by RT-PCR. We provide direct phylogenomic evidence of asymptomatic transmission by constructing the median joining network in the cluster. This data could help us to determine whether the current symptom-based screening should cover asymptomatic persons.