I’ve decided to break my Monday-updates schedule to address a developing COVID-19 story that I’ve gotten a lot of questions about this week.
This week, 239 scientists signed off on a commentary calling for increased attention to the possibility that COVID-19 might be spread by airborne transmission. Yesterday, the World Health Organization released an updated scientific brief acknowledging that COVID-19 might be spread by airborne transmission. If you’re anything like me, then you’ve probably seen a lot of headlines about this, and overheard a lot of discussions about it. So what does it mean?
Let’s get this out of the way first: you may have heard people claiming that if the WHO and CDC were wrong about COVID-19 transmission then they might be wrong about other things. Does this mean we can stop wearing masks and social distancing?
No. No. A thousand times no! If COVID-19 is spread by airborne precautions, then that means we need to be even stricter, not looser, about controlling COVID-19. We’re in the middle of a pandemic, and cases continue to skyrocket in the U.S. and other countries. Don’t give up now.
So what does it all mean? What are droplet and airborne transmission, and why does it matter how COVID-19 is spread?
Droplets are exactly what they sound like: microscopic liquid drops. We all breathe out droplets any time we talk, sing, cough or sneeze. If someone has an infection in their nose, airways or lungs, then they might breathe, sing, cough or sneeze out the virus or bacteria causing their infection in droplets.
Most droplets are relatively heavy – relatively heavy. They’re about the size of a single particle of dust, too small to be seen by the naked eye. However, they are heavy enough that they can only travel forward about 3-6 feet (1-2 meters) before setting on surfaces. That’s why we warn about handwashing and cleaning high-touch surfaces in addition to wearing masks and practicing physical distancing.
Airborne droplets are small enough to float in the air for longer periods of time and spread farther than viruses spread by droplet transmission.
The way that COVID-19 spreads matters for two reasons: because the guidelines that hospitals and healthcare providers follow to prevent the spread of infectious diseases in healthcare settings (infection control precautions) is stricter for diseases spread by airborne transmission than for diseases spread by droplet transmission. The second reason this matters is because if COVID-19 is spread by airborne transmission then people who aren’t wearing a mask could catch COVID-19 even if they’re standing more than 6 feet away from a person with COVID-19 or even if they enter an area after a person with COVID-19 had left it.
The good news is, the infection control precautions that the CDC recommends for COVID-19 are more similar to airborne precautions than to droplet precautions, and in some cases are stricter than airborne precautions.
Additionally, two studies out of Italy and Hong Kong found no healthcare-based spread of COVID-19 when recommended precautions, including wearing appropriate medical-grade face masks, were followed.
However, there have been several identified instances of wide spread of COVID-19 in crowded public locations, including choir practice, church events, funerals and birthday parties, and restaurants. Parties, bars, restaurants, religious services, malls, movies and other indoor activities that attract a lot of other people may still be risky even in states and local areas that have reopened, particularly if you aren’t wearing a mask.
Could COVID-19 be spread by both airborne and droplet transmission? Yes, and it likely may be. For example, measles is spread both by contact with infectious droplets and airborne transmission. To best protect their patients against measles, hospitals and healthcare providers follow the strictest version of infection control precautions – and vaccinate themselves and their patients as well!
So what can we go about it? The authors of the commentary that sparked off this week’s conversation suggested that COVID-19 could be better controlled by improving ventilation, using airborne infection controls and avoiding overcrowding. And continuing hand washing, physical distancing and wearing masks. I want to make it very clear that the authors are suggesting additional precautions but that ventilation does not and cannot take the place of hand washing, physical distancing and mask wear.
Finally, I really, really hope that I don’t need to tell you this, but attending a “COVID party” with the intent of catching and/or spreading COVID-19 is not only stupid, it’s incredibly irresponsible and dangerous. People have died because of COVID parties. Trying to catch COVID-19 or taking a risk with your health as some kind of dare or test or thrill-seeking experience is foolish; intentionally exposing other people to a deadly virus, for any reason, is unethical and flat-out wrong. Do not go to COVID parties.
Stay healthy, stay home if you can, and wear a mask when you can’t stay home.
😷 Dr. B