Big thank you to @EricCarroll for pointing out this new WHO document on SARS-CoV-2 transmission.
This document is pretty complex, in-depth, dense, and I still expect it to evolve as we learn along the way. They have some of the correct people to be working on this, for once. Hello Lidia Morawska signing off on it at the beginning of the forward.
First, a tldr. If you don't care about how it came to be, or the science, and just want to know the outcome, here it is:
https://partnersplatform.who.int/tools/aria
Go to the calculator, enter your data, and come out with a probability of infection in a given situation along with the number of expected secondary infections from that interaction.
Here's the document itself if you want to follow along:
https://iris.who.int/bitstream/handle/10665/376346/9789240090576-eng.pdf?sequence=1&isAllowed=y
Disclaimer - This is evolving science.
I'm going to split this up in a thread, because I took a lot of notes of what stood out to me on a first read, and I hope to come back to it, and use it as a general reference moving forward.
They go on to further define, and discuss, airborne transmission. I have to, again, point out that this is an important step for the WHO to acknowledge and discuss.
"Airborne or Inhalation transmission*: The process whereby aerosolized infectious respiratory particles (IRPs) are inhaled and enter the respiratory tract of a susceptible person, move through the upper and then lower parts of the respiratory tract, and can be deposited on the tissue at any point along the tract, potentially even reaching the distal alveolar region. This mode of transmission can occur when IRPs have travelled either a short or a long distance (range) after emission from an infected person or after resuspension of deposited particles from surface.
The Technical Advisory Group agreed to describe the inhalation transmission mechanism as a sequential five steps or components process with the short- and long- range transmission terms unfolding simultaneously (Figure 2)."
I'll put a brief description of each of the 5 components in the next post.
