On Monday, October 5th the US Centers for Disease Control updated its “How COVID-19 Spreads” web page to include new content under the heading “COVID-19 can sometimes be spread by airborne transmission.” Let’s focus on three questions employers need answered: What? So what? & Now what?
A Message on COVID-19 from WorkSTEPS Chief Medical Officer Dr. Ben Hoffman. Article originally posted at: https://www.worksteps.com/news-and-insights/10-8-10-covid-19-brief-cdc-acknowledges-airborne-transmission-implications-for-employers
CDC Acknowledges Airborne Transmission: Implications for Employers
On Monday, October 5th the US Centers for Disease Control updated its “How COVID-19 Spreads” web page to include new content under the heading “COVID-19 can sometimes be spread by airborne transmission.” Let’s focus on three questions employers need answered: What? So what? & Now what?
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What is Airborne Transmission?
The CDC believes that COVID-19 is most often transmitted through close contact, and happens when an infected person coughs, sneezes, sings, talks or breathes, producing respiratory droplets that are then inhaled or land in someone’s mouth, nose, or eyes.
Monday’s update acknowledges that – in addition to close contact transmission – COVID-19 can be spread through airborne transmission under certain circumstances. Let’s be clear about key terms here:
- Airborne transmission: Means the virus can be carried by droplets that are small enough to hang in the air for hours. Notably, because the droplets are very small, they need to reach a sufficient concentration in the air to be able to infect someone. See this WSJ article for a helpful graphic.
- Certain circumstances: Aerosol transmission depends on two things: 1) The release of tiny droplets into the air; and 2) those droplets achieving sufficient concentration to provide a dose of virus that is enough to cause infection. These two conditions are met when: A) people are indoors; B) the space is poorly ventilated (allowing for the concentration of virus to build); and C) people are not wearing face coverings.
So What? Why Does This Matter?
The acknowledgment of aerosol spread introduces some important exceptions to the rules that have governed prevention strategies:
- Social Distancing: Six feet is not always enough. Very small aerosol particles can travel much farther than six feet.
- Close Contacts: When Contact Tracers look for people who may have been infected by someone diagnosed with COVID-19, they look for people who have been within 6 feet of the infected person for 15 minutes or more. Aerosol transmission breaks both of these rules. If virus-contaminated particles reach sufficient concentration, “close contact” is not required. In fact, COVID-19 can be transmitted even after an infected person leaves the room.
Now What? What Should Employers Do Differently?
First, let’s review the “certain conditions” under which aerosol transmission is thought to occur, namely: A) people are indoors; B) the space is poorly ventilated (allowing for the concentration of virus to build); and C) people are not wearing face coverings.
With these parameters in mind:
- If you have been implementing comprehensive COVID-19 prevention measures, including proper ventilation, you don’t need to change anything.
- However, this new information should motivate all employers to audit their interior spaces, looking for poorly-ventilated rooms being used by employees. In particular, look for conference rooms or break rooms (formal and informal) that have become more heavily used in recent months as employees have returned to work and/or have become less cautious in their behaviors.
- If you haven’t yet adopted a comprehensive prevention strategy, this news is yet another reason to focus on prevention. And if you are struggling to get employees to comply with distancing and mask-wearing, know there is value in focusing on proper ventilation, which will provide protection regardless of compliance.
- Finally, find ways to share this information with your employees. Educate them to identify and avoid poorly-ventilated indoor spaces (bars, restaurants, house parties), and encourage mask-wearing when in public settings outside of work.
The WorkSTEPS COVID-19 Brief reaches literally thousands of corporate health and safety professionals each week. We take seriously our responsibility to identify critical issues and to present important and actionable insights that help people like you keep employees, contractors, families and even communities safer during this pandemic. If there is an issue you’d like to see us address, or if you have any feedback on the job we’re doing, please let us know.
Ben Hoffman, MD, MPH
Chief Medical Officer, WorkSTEPS
For more from Dr. Hoffman, connect with him on LinkedIn.