1. Vaping-related lung illnesses are surging in the U.S. The number of possible cases in which people have been sickened with severe lung illness linked to e-cigarettes has more than doubled to 450 in 33 states, including three deaths and a possible fourth, health officials said.

State and federal health officials are working urgently to understand the causes, but in the meantime, the Centers for Disease Control and Prevention said that “people should consider not using e-cigarette products.” C.D.C. officials said they believed that some “chemical” is involved as the cause, but they have not identified a single responsible “device, product or substance.”