3 ms·
> I remember the original herd immunity was 60-70% and 70% was the high end. Then what's the herd immunity number? The target is 100%-100%/R0. The original CO
by saalweachter 5y ago
> I remember the original herd immunity was 60-70% and 70% was the high end. Then what's the herd immunity number?
The target is 100%-100%/R0.
The original COVID had an R0 of 3-ish, so 60-70% was plenty; delta has an R0 more like 8-9, so the new target is more like 90%.
Typical high-end infection rates were estimated at 25-35% of the population in most of the US after the second wave. 60% vaccination rates plus 35% infection rates gives you about 75% with some form of immunity, which was enough to shut down the original COVID, but not enough to shut down the Delta variant.