Coronavirus can spread through air and environment up to several meters

Can the coronavirus spread through the air and through the environment of patients who are infected with the coronavirus (SARS -CoV-2)? This appears to be possible, researchers from among others Utrecht University (IRAS) and UMC Utrecht discovered based on large-scale research in 28 Dutch nursing homes. The study was recently published in preprint.

After almost two years of a pandemic, everyone knows that the coronavirus can spread through direct contact and at a short distance through large droplets in the air. But what about the spread via small droplets (aerosols) that can travel a greater distance? Hardly any research had been done on this. Moreover, the results from a limited number of foreign studies contradicted each other. 

Researchers from Utrecht decided to investigate this in a large number of Dutch nursing homes. The study was funded by the Dutch organisation for health research and care innovation ZonMw and is part of the COCON consortium - Control of COVID-19 in Hospitals. 

Samples from throat and dry surfaces 

"We managed to measure coronavirus (SARS-Cov-2) in the air in Dutch nursing homes," says Dick Heederik, professor of One Health Risk Analysis and involved in the study. The researchers collected air samples in the rooms of corona patients during outbreaks in Dutch nursing homes. They also took throat samples and samples of dry surfaces in the environment of patients with COVID-19. Furthermore, the researchers collected air samples in communal areas in the nursing homes for four months. In this way, a total of 360 air samples and 319 surface samples were analysed from rooms of COVID-19 patients and communal areas.

"The virus was not found in the smallest particles, so it only spreads to a few metres"

"We found RNA from the virus in a high percentage of air and environmental measurements", says fellow researcher Wietske Dohmen. "This is related to the timing of the study. Infection with the coronavirus occurred relatively recently before, so then patients are still highly contagious." Remarkably, the researchers found the virus virtually not in the smallest particles. "This makes spread at a few metres maximum likely, but much further is significantly less likely", concludes Dohmen. 

Contamination of the environment

The researchers also succeeded in growing the virus from an air sample. This makes airborne transmission likely. "We found SARS-CoV-2 regularly in the air and on surfaces in the immediate vicinity of COVID-19 patients isolated in a room", continued Dohmen. "This indicates contamination of the environment. The environmental contamination of SARS-CoV-2 and infectious aerosols confirm that the coronavirus can spread through the air up to several metres."