This past week I had to complete a "returning to work" module on Covid 19 knowledge for the University of Nevada. While I dreaded completing yet another (boring) on line training, this module actually had some information that I found helpful. I'd like to share a few of these facts as I've found getting good, reliable data about the COVID-19 challenging the past few months.
How many virus particles does it take to become infected with COVID-19? It is estimated it takes approx. 1000 virus particles to become infected with COVID-19. Here is a list of approx. how long it would take to inhale 1000 particles by different activity:
- Breathing: an infected person sheds approx. 20 particles per minute, so it would take about 50 minutes to inhale 1000 particles and potentially become infected.
- Speaking: an infected person sheds approx. 200 particles per minute, so it would take about 5 minutes to inhale 1000 particles and potentially become infected.
- Cough: One cough contains approx 200,000,000 viral particles, so exposure time to inhale 1000 particles is immediate.
- Sneeze: One sneeze contains approx 200,000,000 viral particles, so exposure time to inhale 1000 particles is immediate.
How long does SARS-CoV2 (the virus that causes COVID-19) last outside the body? (From a study and paper by the New England Journal of Medicine, CDC, UCLA, Princeton)
- As an aerosol in the air--up to 3 hours*
- On copper--up to 4 hours
- On cardboard--up to 24 hours
- On plastic--2-3 days
- On stainless steel--2-3 days
*Researchers used a nebulizer to simulate coughing or sneezing and found that the virus became an aerosol.
Because the SARS-CoV-2 virus may remain viable on non-porous surfaces for several days, you should disinfect surfaces using a product that meets the EPA criteria for use against the virus. The University of Nevada uses TB-Cide Quat to disinfect. An important note. There is a difference between cleaning (wiping off dirt/grime) and disinfecting a surface. To disinfect, you need to spray the surface from approx 6" away, and allow the disinfectant to sit on the surface for approx. 2 minutes. You can then wipe the surface off, and finish by washing your hands.
So friends, wear your mask, wash your hands, and stay safe.