There are a few reasons for the rapid spread in various areas:
Italy: the soccer game may have been one but, probably more importantly, the focus should be on the fact the Italians have given up control of their textile industry to the Chinese who happily produce clothing there with the "made in Italy" label. Much of the work is apparently done by Chinese nationals who number over 310,000 in Italy, including over 30,000 in the city of Prato (near Florence).
New Orleans: Mardi gras was held on February 16 and we're now five weeks beyond that date, so take a guess why they have such a big problem. And, it's not just the day itself that matters when you consider how a virus can spread through a population. Consider how many people in the region work on the floats, and prepare all sorts of other facets of the parade, the meals, the drinks, etc. Made for boosting the spread of the virus.
New York Metro area: Lots of people, lots of events, lots of socializing in tight quarters, riding the subway, etc.
Saw some video tonight of the Mayor and the city's Health Commissioner both telling people on February 2, to go out and enjoy themselves and urging them to attend the Chinatown Lunar New Year Parade and Festival on February 9.................about six weeks ago and New York is our epicenter.