A few hypothesis, in order of preference: - Most of the infections come from "superspreader" events such as large gatherings where vaccination is mandatory -

A few hypothesis, in order of preference: - Most of the infections come from "superspreader" events such as large gatherings where vaccination is mandatory - Children, who make most of the unvaccinated, are less affected - Vaccinated cases are detected earlier, possibly because they get symptoms earlier - Delta outcompetes omicron among people with no immunity