I’m not sure we, as a population, are thinking of herd immunity the way we should be for this virus. It might not be a simple test for antibodies that is going to tell us that, as it would for chickenpox, for instance.
There’s some newer info that suggests other things are at play besides antibodies- T cell memory of prior coronavirus infections (which we all have had). Some people who were asymptomatic or never got infected in the first place may have this type of immunity, which is hard to test for.
Remember, we have never had a coronavirus pandemic before.
It may be that NYC does indeed have herd immunity, if you put these two types of immunity together.
Also, a new paper in The Lancet just came out that showed that the shutdowns didn’t prevent cases, but spread them out through time so people could be properly cared for, which was the original intention of the shutdowns, as the scientists who developed the protocols have maintained all along.
This leads me to believe that the people in NYC, for instance, who were going to get it have mostly gotten it, though masks and whatever is left of the other restrictions are still keeping that number down. If those are lifted, there will be more cases, but then that may be all there will be. I personally hope mask mandates stay in place until there is a vaccine.
So I’m going to be a bit more optimistic- I think that COVID will be part of the background ILIs we have around, but much better than it is now. Nationally (except for CA) we’re at or just past the peak. I don’t think that there will be a second wave, but there will be cases occurring continually until most susceptible people have had it or there’s a vaccine. So I do agree with the Oxford don, although I’m sure he thinks there are far more susceptible people out there than I do.
Long story short- I think both UOR and WDW will be just fine.