Small but important correction: nothing can make epidemiological spread non-exponential. Driving base reproduction below one additional infection per infected patient means the exponent is less than one, so the incidence of the disease rapidly decreases. This decrease is
also exponential by definition: infection is simply an exponential process, and an exponential equation doesn't stop being what it is when the exponent is less than one.
The steady state is exactly 1, which is like balancing a pencil on its point.
It's plausible that two things happened here: the various local restrictions reduced the R0 of flu below 1, and the border closures kept mutations from traveling: and influenza is notoriously mutation-prone.
These can combine to practically extirpate influenza. Unfortunately, the effect is temporary, and the next flu season is likely to be a real doozy.
Which will be "fun" because our societies now have a hyperactive immune system, and there will be considerable political pressure to "do something" about the next flu wave. This must be resisted but I'm not optimistic.
The steady state is exactly 1, which is like balancing a pencil on its point.
It's plausible that two things happened here: the various local restrictions reduced the R0 of flu below 1, and the border closures kept mutations from traveling: and influenza is notoriously mutation-prone.
These can combine to practically extirpate influenza. Unfortunately, the effect is temporary, and the next flu season is likely to be a real doozy.
Which will be "fun" because our societies now have a hyperactive immune system, and there will be considerable political pressure to "do something" about the next flu wave. This must be resisted but I'm not optimistic.