That's basically the headline of this Guardian article. Technically, I think there should be a hyphen there, because this isn't about an alarming epidemic that just happens to involve clowns, it's about an epidemic of clowns who are themselves alarming. But since such an epidemic would in fact also be alarming, I will let that one slide.
Probably inspired by the spooky clown who was recently spooking people in Northampton, England, people dressed as clowns or wearing clown masks have reportedly been alarming people in Norfolk (also England). Police said that no one had been injured or assaulted, but that in both cases to date "the callers reported being alarmed" and were chased a short distance by the clowns.
A police superintendent urged calm, saying that the clownish individuals are probably just trying to get attention, and that ignoring them might be the best way to go. "Firstly," he noted, "I'd like to stress that it isn't against the law to dress up as a clown." (Maybe not, but remember that at least in the U.S. and Canada, it is illegal in many places to wear a mask at least in some circumstances.) He went on to remind citizens that so far no one has actually suffered a clown assault, "and it appears that the people involved are waiting for a passerby to be startled by their appearance and run away, and then the [alleged] clown runs after them for a short distance.... The most effective way to behave if you are to see someone dressed up [as a clown] is to give no reaction—because that's what they are after."
A third case was reported on Friday in the same area. In that one, witnesses reported the clown was wearing a "blue and red 'onesie' clown suit" along with a red wig and white face mask, and—maybe most alarming of all—he drove off in a white van.
Never one to go in for sensationalism, the Daily Mirror ran the photo above (from the movie IT) along with its story on that case, but did note that "this is a file picture." So, nothing to be alarmed about.