Significant proportion of hospitalized COVID-19 patients are asymptomatic

Editor's Note

This study from the University of Louisville School of Medicine, Louisville, Kentucky, shows that the proportion of asymptomatic patients admitted to the hospital with COVID-19 is significant, and why universal testing is important to prevent hospital-acquired infection.

Of 2,882 patients admitted to the hospital, 103 were COVID-19 positive. Among the 103 positive patients, 65 (63%) were symptomatic and 38 (37%) were asymptomatic.

The proportion of asymptomatic COVID-19-positive patients varied over the duration of the 12-week study period but trended up from 20% at the beginning of the study period to 60% at the end.

The most common populations of asymptomatic patients were trauma and obstetrics.

Identifying and isolating asymptomatic patients likely prevented exposure and development of hospital-acquired COVID-19 cases among healthcare workers and other patients, the researchers say. Universal surveillance testing for COVID-10 was started at the University of Louisville Hospital in April 2020.