Multiple studies and numerous articles warn that the planet is in the throes of a loneliness pandemic. The British government created a Ministerial Lead for Loneliness position in 2018. Japan followed suit in 2021, making its Minister of Loneliness an official cabinet post.
As threat levels go, this may not seem on par with the Cordyceps outbreak that destroys the world in "The Last of Us," because its symptoms aren't discernible to observers or tangible.
Neither did it sweep the world overnight...