全国の水道の放射能濃度

In the last week, leading epidemiologists from respected institutions have, through different methods, reached the same conclusion: About 85 to 90 percent of the American population is still susceptible to SARS-CoV-2, the virus causing the current pandemic.

The number is important because it means that “herd immunity” — the point at which a disease stops spreading because nearly everyone in a population has contracted it — is still very far off.

WASHINGTON — Top White House officials pressured the Centers for Disease Control and Prevention this summer to play down the risk of sending children back to school, a strikingly political intervention in one of the most sensitive public health debates of the pandemic, according to documents and interviews with current and former government officials.

As part of their behind-the-scenes effort, White House officials also tried to circumvent the C.D.C. in a search for alternate data showing that the pandemic was weakening and posed little danger to children.