The latest on Covid-19

As case counts grew in the U.S. and Europe, countries like France, Germany, and Spain imposed new restrictions on businesses and gatherings. The Trump administration declared a national emergency and expanded its travel prohibitions to the U.K. and Ireland — a step experts have said won't address the ongoing viral spread in U.S. communities and that led to chaos at U.S. airports. The CDC called for canceling or postponing events of 50 or more people for the next eight weeks.

The pandemic was also the leading issue at Sunday's debate between Democratic presidential candidates Joe Biden and Bernie Sanders.

Other news:

The FDA has given the green light to additional Covid-19 tests, as the government tries to repair its fumbled testing rollout. The administration said it would launch a mobile testing system this week, while Verily's online screening tool will initially be more limited than Trump had suggested.
Officials are concerned that countries might nationalize response supplies, fueled by a disputed report that the Trump administration tried to secure rights to an experimental vaccine.
Some hospitals reported Covid-19 infections in health care workers (the NIH confirmed an infection in an employee as well) and warned of shortages of masks, gowns, and other supplies. Here's more on how health workers are faring.
The ripple effects of the pandemic grew, as institutions like Harvard and the Broad shut down some research labs.