There is a new variant of the coronavirus to keep under control – indeed, a variant of the variant: it is the AY.4.2., Also called Delta plus because it is a mutation of the Delta (the “Indian variant”, for those who have been attacked to the old denomination). In England, Delta plus is the cause of about 10% of covid infections, but for now it is difficult to understand what its evolution will be: here is what we know and what lessons we can draw from this umpteenth change of course of the SARS-CoV-2 coronavirus .