stem from more factors like the one given above.
Yes, it's multi-factorial.
* Lockdowns and how they are easened/tightened (especially kindergarten and schools, home office, ...)
* People not being transmitters because they had it already
* People not being transmitters anymore because they're dead already
* Seasonal influence (People ventilating more, staying less inside, UV light, Vitamin D status, ...)
* Vaccinations
* Countries having different age structure (e.g. Germany has a lot of old people)
* Countries having different living structure (e.g. multi generational homes in Italy but not in Germany)
* etc etc etc