Determinants of pandemic performance has proven to be very multi-factorial, but from day one, urban density has not that been significant a factor, especially in richer countries. The initial wave just looked urban because the virus reached each _country_ via internationally-connected urban centers.

Given that pandemic spread has almost entirely played out indoor, a much more likely risk factor is multi-member (and especially multi-generational) households. As mentioned in the article, Sweden and the rest of Scandinavia have a small household size and especially high proportion of single-person households.