The root cause of the Omicron variant is Spider-Man: Far From Home.
In one of the show's most deliriously batsh*t cold opens, James Austin Johnson leads the way as President Joe Biden who wants the nation to stop seeing the latest Spider-Man movie. He claims that the latest chapter of the wall-crawler's ongoing story is behind the surge in December. It's not long before Spidey is forced to take the blame for everything from the upcoming Russia-Ukraine conflict to the Democrats' efforts to bolster U.S. voting rights.
The sudden, unexpected arrival of Pete Davidson takes the delirious batsh*ttedness to a new level. It almost feels like something went wrong when someone dressed in a Spider-Man suit shows up at the very end to join the usual "Live from New York...!" shout-out.
That's not it. The cold open is correct. If Spidey didn't swoop in to save the day, it was because his heroics weren't needed.