I agree that this is a relative weakness of the model. I think part of it is that the division into vulnerable/invulnerable is a simplification. If for instance you injected somebody with COVID then everybody would be “vulnerable”. So in some environments conditions are ideal for spread which makes many relatively immune people become infected.
I agree that this is a relative weakness of the model. I think part of it is that the division into vulnerable/invulnerable is a simplification. If for instance you injected somebody with COVID then everybody would be “vulnerable”. So in some environments conditions are ideal for spread which makes many relatively immune people become infected.