“...could be related to better treatment, rather than vaccine efficacy.”
OR less virulent virus OR greater natural immunity in the population over time.
Yes, less deadly mutation/submutation is a possibility. I was speaking of the daily death numbers only not infections. Maybe natural immunity is a factor but one would suspect very few cases of double-infection ending up in the hospital... unless the strain has so mutated that it’s unrecognizable, but nobody has broached that subject not even with Omicron!