“Gee I wonder why”
Masks. Same thing happened in Australia and Chile in their winter.
I am sure masks also cut down cold infections as well. Thus based upon the principle that whatever reduces infections is worth it, then masks can be mandated every year. But dealing with the actual reason that so many die of Covid - that of America being in the worst health (70% Americans overweight, 42% obese; 100 million w/ high blood pressure; 23 mil w/ type 2 diabetes) ever relative to our standard of living - is hardly made a priority. Stay sheltered and if you go out then you cannot breath or interact socially normally. I am almost 69 and was active and without a mask in this crowded city from Spring to Fall - thank God - until it became required. No one i interacted with got Covid, and I must likely had it last Feb. and with mild symptoms.