Presymptomatic transmission of COVID-19 in a cluster of cases occurred in confined space: a case report

Abstract Background : COVID-19 is spreading rapidly intercity and international despite rigid public health prevention and control measures been taken. Case presentation : In a cluster of infection, six out of seven participants engaged in persistent singing and talking in confined space were later diagnosed COVID-19 patients. One of the cases was asymptomatic with no SARS-CoV-2 nucleic acid detected, but positive for anti-SARS-CoV-2 IgG. None of the household contacts was infected during the following month. Conclusions : This epidemiological evidence revealed that asymptomatic patients transmitted the coronavirus in confined space with relatively high efficiency, suggesting that it is important to provide better ventilation in public buildings to prevent COVID-19 transmission.