The United States has surpassed 250,000 coronavirus deaths as new cases surge in many parts of the country.
New York City on Wednesday announced the closure of its school system, the nation's largest, with the city recording a seventh consecutive day with a COVID-19 positivity rate above 3%.
"Public school buildings will be closed as of tomorrow, Thursday Nov. 19, out [of] an abundance of caution. We must fight back the second wave of COVID-19," New York City Mayor Bill de Blasio wrote on Twitter.
In-person school resumed for New York children between late September and early October, when the seven-day positivity rate was under 2%.
Other major cities, including Boston and Detroit, have made recent moves to halt in-person classes for their schools.
Across the United States there have been more than 11.5 million confirmed cases since the pandemic began.
The current wave of infections is adding to that number at an increased rate with an average of nearly 160,000 new cases each day during the past week. That is about triple the number of new daily cases in the United States one month ago. More than 1,100 people are dying per day.
Health care workers are dealing with the strain of a record number of hospitalized COVID-19 patients.
The surge has pushed leaders in many states to reimpose certain restrictions in order to try to slow the spread of the virus.
Among the latest, Minnesota Gov. Tim Walz announced Wednesday that all restaurants, bars and gyms would close for four weeks. Minnesota is adding four times as many new infections each day as it was in mid-October.
Officials are expressing concerns about the approaching Thanksgiving holiday, a time when millions of Americans typically gather with family members and often travel to other parts of the country.
Virginia Gov. Ralph Northam urged people in his state to stay home, saying doing so would be "an act of love." He added that if people do decide to celebrate with others, they should do so in small groups and be outdoors.
U.S. Health and Human Services Secretary Alex Azar urged similar caution in a Wednesday briefing.
"Gathering indoors with people who aren't members of your household is a high-risk activity for spreading the virus," he said.
There has been some optimistic news this week with two pharmaceutical companies announcing preliminary results showing their COVID-19 vaccines have been effective in trials.
Azar said those developments mean that within weeks the Food and Drug Administration could authorize the vaccines and they could be ready for distribution.
"Because of this work, by the end of December, we expect to have about 40 million doses of these two vaccines available for distribution, pending FDA authorization-enough to vaccinate about 20 million of our most vulnerable Americans-and production would continue to ramp up after that," Azar said.
The U.S. government has pursued a vaccination development program with the intention of making it so that no one in the country has to pay out of their own pocket to get a vaccine.