Headlines like this one – “Choir practice turns fatal. Airborne coronavirus strongly suspected” – point to a difference between how epidemiologists might define “airborne” vs. how others might think about the word. latimes.com/world-nation/s…
60 singers in a town north of Seattle had choir practice for 2.5 hours; noone had symptoms of COVID-19. Tragically, now 45 of those singers have tested positive, 3 are hospitalized, and two have died, and clearly the choir practice was the place where they became infected.
The singers stayed apart and didn’t come into physical contact. Given these circumstances, most if not all were infected via virus expelled by an asymptomatic person that spread via the air to others. Is this not airborne transmission?
It indeed looks like transmission via air, rather than direct contact. An epidemiologist might fall back on a stricter definition of “airborne”: viruses that can float in the air for long periods of time – up to hours – and travel long distances and still infect people.
It's not clear that this virus can do that. Still, the events here show there are circumstances coronavirus can spread via ‘aerosols’, or droplets of very small size that might linger in the air for minutes at a time. Singing is a good way to expel droplets and smaller aerosols.
This is definitely a grey area. The WHO, for example, says “airborne transmission may be possible in specific circumstances and settings in which procedures or support treatments that generate aerosols are performed.” who.int/news-room/comm…
Singing may generate the same kinds of aerosols WHO is concerned about with certain medical procedures. So, in the end, perhaps the difference between spread via aerosol and “airborne” spread is not all that great.
This Wired article does a great job diving into this grey area. The lesson is probably that we shouldn’t be so rigid and apply black-and-white definitions for what is airborne vs. non-airborne. wired.com/story/they-say…
Practically speaking, we should be aware that there are circumstances in which this virus can spread by very small droplets carried through the air, and take measures to reduce our risk accordingly. The CDC already recommends airborne precautions for health workers.
