The C.D.C. Has New Covid Guidelines. This Is What It Got Wrong.

For nearly two years, American officials have changed recommendations on how to manage the coronavirus. On Monday we got one of the biggest shifts yet: Infected people, who had long been told to isolate for at least 10 days, now have to isolate for only five days if they feel fine, regardless of vaccination status. On one level, this decision by the Centers for Disease Control and Prevention is a welcome nod to science and practicality because many people aren’t infectious for such a long period.

But the change doesn’t grapple...