For weeks, the most pressing policy challenge has been relieving the life-and-death pressure on our hospitals. But all that justifiable emphasis on flattening the curve may have created a dangerous illusion that we can get away with relatively small infection rates.
It’s easy to forget that if a disease can’t be contained — and it’s too late for that in the COVID-19 pandemic — then there’s only one possible ending to the story: We must collectively develop immunity to the disease. In lieu of a vaccine, that means most of us will need to be exposed to the virus, and some unknowably large number of us will die in the process.
This is the simple, scary math that Harvard epidemiologists Marc Lipsitch and his colleague Yonatan Grad have tried to convey in a series of recently published papers: If each person infected with COVID-19 disease in turn infects three more, as we now think, then in order to bring the disease to heel, Grad says, two of those people must already be immune.