QTing my reply so I can thread some thoughts I keep having about the relationship between contagiousness and severity of diseases.

I have no background in any of this and I don’t know what I’m talking about.

But seems like typing stuff out is good for learning... https://twitter.com/andrewstepner/status/1342748042340941829

Mechanisms that tie more contagiousness and less severity:
-people who are sicker stay home and isolate more
-dead people often can’t transmit viruses (seems maybe irrelevant for covid on the current margin bc people are already not contagious when they typically die?)

-if a lower initial dose is needed to infect someone, then more of the cases will have low initial viral load and that correlates with less severe disease course?? (I’m unsure if this logic holds)

-something where upper respiratory symptoms are more what makes viruses contagious and lower respiratory symptoms are what cause more serious problems? (Why not both though—maybe this isn’t a different thing from the first thing?)

Something about presymptomatic transmission being one of the main drivers of contagiousness, and if the virus is replicating without totally screwing you over for many days, then it means your immune system has a lot of time to catch up with it?

OTOH, smallpox is quite contagious despite being serious. And my impression is that most of the spread from that is through the air and not the sores, but that might be totally wrong.

Measles is extremely contagious, definitely though the air, and also fairly serious, and I don’t really have any idea why it’s so contagious compared to other stuff that’s also spread through aerosols.

Maybe it’s not but no one tracks most mild colds in immune-naive populations?

Also just in general, except for the fact that they cause people to stay home, it seems like basically all non fatal symptoms of disease make the disease more contagious. And higher viral load makes people more contagious.

So that would lean in the opposite direction, right?