California shut down very hard and fast. When they reopened, nearly 100% of the population was still susceptible to the virus, so it spread like wildfire. Especially since the reopening was not exactly slow. Compare this to the Northeast and much of Western Europe where the virus spread too quickly until lockdowns reduced the spread. Now, keeping the transmission rate low in those areas has become comparatively easy,…
I think it would mean, even in NYC, its current "herd immunity" would reduce the so-called R value by only 20%. That doesn't sound enough to explain the difference between NY and CA.