The idea of building herd immunity – increasing the number of infected to such a degree that naturally occurring immunity would outstrip the coronavirus, while isolating the elderly and others at greatest risk of the disease – has been tossed around in the United States, the United Kingdom and elsewhere. This week, however, U.K. officials appear to be backing away from that approach. But the kind of “herd immunity” strategy being discussed in the U.K. does not acknowledge a critical…
