I updated the post to distinguish between respiratory droplets and a fully airborne route of transmission.
We still don’t know whether COVID-19 (or SARS) is transmitted only through respiratory droplets, or whether it is airborne more broadly in smaller droplets beyond a range of 6′ or so. If that’s the key difference between a widely transmissible disease and one that’s less of a threat, and there’s a lot of variability among respiratory illnesses, then that would make it less likely a priori that a novel respiratory illness is highly contagious.
On the other hand, it might be that respiratory droplets vs. fully airborne is not the key difference, or of most diseases spreadable by droplets are also aerosolized.
To tell what we’re dealing with, we might look for suggestive case studies. There was a choir that met in the early days of COVID-19 where none of the members were sick, they all stayed 6′ apart, but half the choir still caught COVID-19 from each other. This suggests COVID-19 is fully airborne, though of course it’s not hard evidence.
But in general, this model is designed to help with ‘fog of war’. Since we can’t know these factors for sure, we use what evidence is available to reason under uncertainty. My historical research both into COVID-19 and historical diseases suggested to me that this model is fairly well-calibrated, but there just aren’t enough data points to know for sure. Even if not, though, it at least serves as guideposts for future reasoning, and I think that’s valuable.
We still don’t know whether COVID-19 (or SARS) is transmitted only through respiratory droplets, or whether it is airborne more broadly in smaller droplets beyond a range of 6′ or so.
And if it is airbone in smaller droplets whether it is outside of specific medical procedures airbone in that way.
I updated the post to distinguish between respiratory droplets and a fully airborne route of transmission.
We still don’t know whether COVID-19 (or SARS) is transmitted only through respiratory droplets, or whether it is airborne more broadly in smaller droplets beyond a range of 6′ or so. If that’s the key difference between a widely transmissible disease and one that’s less of a threat, and there’s a lot of variability among respiratory illnesses, then that would make it less likely a priori that a novel respiratory illness is highly contagious.
On the other hand, it might be that respiratory droplets vs. fully airborne is not the key difference, or of most diseases spreadable by droplets are also aerosolized.
To tell what we’re dealing with, we might look for suggestive case studies. There was a choir that met in the early days of COVID-19 where none of the members were sick, they all stayed 6′ apart, but half the choir still caught COVID-19 from each other. This suggests COVID-19 is fully airborne, though of course it’s not hard evidence.
But in general, this model is designed to help with ‘fog of war’. Since we can’t know these factors for sure, we use what evidence is available to reason under uncertainty. My historical research both into COVID-19 and historical diseases suggested to me that this model is fairly well-calibrated, but there just aren’t enough data points to know for sure. Even if not, though, it at least serves as guideposts for future reasoning, and I think that’s valuable.
And if it is airbone in smaller droplets whether it is outside of specific medical procedures airbone in that way.