Sanctuary cities with huge homeless and filth problems, ready and willing to become hotspots for the virus. And waiting to cry “Emergency” on Chuck Schumer’s que.
Because of the new ability to work remotely it's time to re-think the whole idea of having cities, subways, commuter rail, tall buildings, elevators, department stores. Collectively all this adds up to a mass virus manufacturing and distribution system. When someone catches a virus and works in a tall skinny skyscraper, the whole tower turns into a hospital ward with coughing and sneezing for months.
Gaia is trying to kill us, and will win some battles. Don't give her easy targets. Big cities are a relatively new evolutionary experiment and it's not working out well.