Rarely

In another unexpected and unwelcome twist in the pandemic, the Centers for Disease Control and Prevention released a report on Friday strongly suggesting that fully immunized people with so-called breakthrough Delta variant infections can…

Since the beginning of the pandemic, very few young people have become so sick with Covid-19 that they have to be hospitalized. But of those who did, about a third were admitted to intensive care units and 5 percent required ventilators,…