The Dizzying Chaos of Calculating Your Covid Risk

In lieu of coherent public guidelines, most of us resort to incoherent private rules

A Thanksgiving traveler at John Wayne Airport in Orange County, CA. Photo: Allen J. Schaben / Los Angeles Times via Getty Images

Riding the New York City subway recently, I noticed that just about every advertisement — at least all the ones directly in my sightline — seemed to be public service messages about Covid-19 safety. There were cartoon graphics showing how…