Don Milton
June 1, 2020

Don Milton co-authored a study to understand the patterns of contamination of SARS-CoV-2, which causes COVID-19. Researchers say it's essential for prevention policies and effective interventions.

Currently, it's unknown if asymptomatic individuals pose the same environmental contamination risk as symptomatic ones, although viral shedding has been demonstrated to continue even after clinical recovery of COVID-19 patients.

"...Viral contamination of the air and surfaces surrounding asymptomatic or recovering COVID-19 patients could have serious implications for outbreak control strategies," the study states. 

Sampling was conducted in three airborne infection isolation rooms in the ICU and 27 AIIRs in the general ward on surfaces surrounding hospitalized COVID-19 patients at different stages of illness. 

Researchers found that 56.7% of rooms had at least one surface contaminated, and that concentrations of SARS-CoV-2 in the air and high-touch surfaces could be highest during the first week of COVID-19 illness. They also found that although SARS-CoV-2 can be shed in the air, more data would be required to confirm its potential airborne spread. 

"Further work is urgently needed to examine these findings in larger numbers and different settings to better understand the factors affecting air and surface spread of SARS-CoV-2 and inform effective infection prevention policies," researchers wrote. 

Milton is a professor of environmental health and an expert in aerosol transmission. He assisted with the design of the experiments and the interpretation of the data. 

He is currently conducting a study of how SARS-CoV-2 spreads via exhaled breath and how well masks work to prevent or reduce the shedding of virus into the air. Learn more about the study at

Related Links

Nature: Detection of air and surface contamination by SARS-CoV-2 in hospital rooms of infected patients

UMD SPH Covid-19 Surveillance Study - Now recruiting study participants