How is COVID Spread? Droplet? Aerosol?
Justin Morgenstern, MD
- There is ongoing debate about how important aerosols are in the transmission of COVID-19. Based on the best available evidence, it appears that they play an important role.
- There is actually no direct evidence that COVID-19 is spread through droplets. Arguments for droplet spread tend to focus on comparisons to measles (using factors like Ro), but these arguments are dubious.
- Multiple lines of evidence, including animal studies, super-spreader events, the importance of ventilation, and the fact that being outdoors is protective, all point to an important role of aerosols in the transmission of COVID-19.
- We need to continue our current efforts focused on masking and physical distancing, but increase efforts aimed at controlling aerosols, such as improving ventilation.
- Our experience to date illustrates that the absolute risk to healthcare workers is relatively small. We should aim to have airborne precautions available for all healthcare workers interacting with COVID suspected patients, but while PPE shortages are a reality, we may need to make pragmatic decisions. Risk will be highest when spending longer times in close proximity to patients with respiratory symptoms.
COVID-19 is spread by aerosols: an evidence review. First10EM.com
Shirin M. - December 3, 2020 10:02 AM
Ugh--I wished I could un hear this--I liked the optimistic note at the end--but still,.... can I just still be in denial and pretend covid is only spread via droplet?
Justin M. - December 3, 2020 12:18 PM
I am sorry. I really didn't want to provoke negative psychologic reactions, and I am truly optimistic that this gives us a better path forward. The worst scenario I can imagine involves shaping our COVID response without science (any more than we already have). Please stay safe out there. All the best - Justin
Dallas H. - December 3, 2020 1:05 PM
Great piece, thank you Justin.
Ian L. - December 3, 2020 3:13 PM
There are face shields with the surgical mask or and goggles .
You can get uvex bionic face shields that extend to the neck and are reusable they are in the range $A30-55 BUT have no idea how many there are . "Every person should have a face shield " wrote DR Michael Edmonds- infectious disease physician and hospital epidemiologist. IN UCSF podcast july 16 2020 this issue discussed . Dr D Milton Dr M Ghandi Dr Michael Edmond -Dr Michael Osterholm special advisor to President Elect Joe BIDEN is for opening windows and outdoor classes whenever possible in schools and Dr George Rutherford of head of disease and global epidemiology states ":Open the damn windows and let them wear coats " Buffalo News Nov 5 2020 .
brendan c. - December 4, 2020 10:22 AM
I think you said most hospital have excellent ventilation. Our ER has doors shut and no windows like every other ER in the country. Where is the ventilation?
We have set up HVACs and have a few negative pressure rooms but I would not characterize the ER as a whole as having "excellent ventilation.". Does yours?