December 27, 2020

Coronavirus Transmission

El Pais has an excellent write-up on what is known about transmission of Covid-19 (SARS-CoV-2). A few key points to take away are first about the three main modes of transmission:

  1. Droplet transmission: respiratory droplets are 300 micrometers or larger and fall to the ground within seconds.
  2. Aerosol transmission (airborne): aerosols are much tinier respiratory droplets, less than 100 micrometers in size, and can remain suspended in the air for hours on end.
  3. Fomite transmission: surface contamination, which has not yet been linked to any cases worldwide.

The visuals in this article are very helpful to show how these aerosol particles are released and how they fill spaces. Since interpreting situations often involve multiple people speaking within a small space, this is an important detail:

…speaking in a loud voice releases 50 times more virus-laden particles than when we don’t speak at all. These aerosols, if not diffused through ventilation, become increasingly concentrated, which increases the risk of infection. Scientists have shown that these particles — which we also release into the atmosphere when simply breathing and which can escape from improperly worn face masks — can infect people who spend more than a few minutes within a five-meter radius of an infected person, depending on the length of time and the nature of the interaction.

Properly worn masks, so that both the nose and the mouth are completely covered, are effective, but are also not 100% effective at preventing transmission.

I’m very conscious about how speaking is releasing aerosols now, and this is why I wear an N-95 mask for all work performed in person, regardless of setting. This is the best way to how to protect myself and those I’m working with, if the situation necessitates working together in-person. Otherwise, I am erring on the side of working remotely over video.

Via Kottke, who has an excellent collection of resources related to Covid-19 that I reference often.

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