How is COVID-19 transmitted?

 COVID-19 is transmitted largely by the airborne route on tiny particles called aerosols, not by contact or much larger droplets as originally thought.

This means it can linger in room air for hours and can travel under doors, along corridors, and occasionally even through ventilation shafts. Think cigarette smoke.

Increasing room ventilation reduces the amount of germs in the air and makes catching COVID-19 less likely. The CO₂ level in room air can be used to indicate how well ventilated it is.

Watch the very short videos in the Tweets below to see how airborne germs spread like a mist or smoke:

“When we breathe or talk or sing or shout, we all generate really fine droplets known as aerosols, and they stay in the air for a really long period of time. It’s a significant route of transmission between people, so we can’t ignore it.” – Kate Cole pic.twitter.com/5iWKGSc9Jg

— abc730 (@abc730) January 19, 2021

2) VENTILATION is key. Both ventilation and masks needed to reduce risk indoors. But most buildings not ventilated well enough.pic.twitter.com/qhz8cs0grH

— Eric Feigl-Ding (@DrEricDing) January 19, 2021

 
This four-minute video by Professor Shelly Miller of the University of Colorado provides an excellent summary of how respiratory infections are transmitted through the air and is well worth watching:

Why surfaces and contact are not the major mechanism of spread:

I wrote again about hygiene theaterhttps://t.co/uOPvCJeAqA

Restaurants, gyms, urban transit authorities, and more are still power-scrubbing their way to a false sense of security even as the evidence piles up that surface transmission of COVID-19 is, at best, extremely rare

— Derek Thompson (@DKThomp) February 8, 2021

“We don’t have a single documented case of covid-19 transmission from surfaces. Not one.”

“So why, then, are we spending a small fortune to deep clean our offices, schools, subways and buses?”

My oped w @linseymarr @ProfCharlesHaas from Novhttps://t.co/t0Kuvf0vL9

— Joseph Allen (@j_g_allen) February 8, 2021

For more detailed information, this academic review paper by some of the world’s leading scientists provides an excellent summary of the knowledge at the end of 2020. Click on the image to open the paper in a new window:

The last word on this matter of airborne transmission, which all sensible authorities now agree is the most significant method of transmission, goes to Professor Baxter:

Experts who continue to deny airborne tranmission of COVID19 are frankly in denial. And we need to stop giving them airtime. Forgive the pun, but doing so is literally killing people

— Nancy Baxter MD PhD (@enenbee) February 4, 2021