Who Invented the Phrase “Social Distancing”?

The World Health Organization would like to retire the phrase “social distancing” in favor of “physical distancing.” Their logic is impeccable: viruses are transmitted when you get physically close to another person, not when you’re chatting on FaceTime or holding a virtual meeting on Zoom. As long as you’re physically separate, you should feel free to be as social as you want.
Fine. But that got me curious: who came up with phrase social distancing in the first place? Does it go back to the 1918 flu pandemic, when physical distancing and social distancing were more or less the same thing, so no one cared about the distinction? Or what?
This turns out to be surprisingly hard to get a handle on. I am, obviously, talking about social distancing as a phrase that refers to a way of fighting epidemics. I don’t care about crinoline skirts or the social habits of the 16th century Spanish court. The concept of social distancing as a way of keeping your inferiors in their place goes back quite a ways.
But in the current epidemiological sense, it doesn’t seem to go back even to the start of the century:
So circa 2003 it is, unless someone comes up with something better. But who coined the phrase? And why did they choose to call it social distancing? In 2003 there was obviously a world of difference between social and physical distancing. Is there anyone out there who wants to take the blame for this?