littlebabyjesus
one of Maxwell's demons
With the proviso that this is in no way proven, the patterns of infection worldwide, including what is happening in the Americas now, are still consistent with the development of some form of population-level resistance being a factor in play during recovery from a severe outbreak. There is one possible candidate contributory reason for this - the presence of certain T cells that recognise covid proteins in perhaps half the population, discovered in a study looking at vaccines last month.It's hard to get a grip on what the risks are now that the country is opening up again. If you look across the Channel Europe seems to be opening up without a major second spike in infections, even if there's local flare ups here and there. But look in the other direction across the Atlantic and things don't look to be going so well.
Not knowing if or how much this is a factor means you can't just thrown doors open again, but I would suggest that it is at least something that should be considered when working out what to try reopening. Much of the UK is in the 'coming out of a severe outbreak' category. A bit more honesty wouldn't go amiss - ie we don't know what the risks are exactly (or even approximately, really), so we're going to try this and monitor the effects and then reverse the decision swiftly if it doesn't work.