@augieray

3.7 months is horribly short.

As bad as things are it is hard to believe that interval would be for the population as a whole. But we hardly test anything in the west so we really don't know.
I tried to find out how they calculated those intervals but couldn't find a source closer to the researchers (no Japanese skills I'm afraid...).

I suspect those numbers could be biased towards a subset of the population that is being reinfected very often, and not necessarily representative of the whole population (depending on how they are calculated). Or maybe not.

Given the overall lack of concern and empathy, a very unevenly distributed burden is a horrible scenario. Of course, those that are being hit more often might just be further along the road, with more joining in soon.