Coronavirus cases surged to a new record on Monday, with the US now averaging 111,000 cases each day for the past week, a grim milestone amid rising hospitalisations and deaths that cast a shadow on positive news about the effectiveness of a potential vaccine.

As the number of infected Americans passed 10 million and governors struggled to manage the pandemic, President-elect Joseph R. Biden Jr tried on Monday to use his bully pulpit — the only tool at his disposal until he replaces President Trump in 72 days — to urge Americans to set aside the bitterness of the 2020 election and wear a mask.

“It doesn’t matter who you voted for, where you stood before Election Day,” Biden said in Delaware after announcing a Covid-19 advisory board charged with preparing for quick action once he is inaugurated. “It doesn’t matter your party, your point of view. We can save tens of thousands of lives if everyone would just wear a mask for the next few months. Not Democratic or Republican lives — American lives.”

Hours before Biden’s remarks, the drug maker Pfizer announced that an early analysis of its coronavirus vaccine trial suggested the vaccine was robustly effective in preventing Covid-19, a promising development that sent stock prices soaring. The world has waited anxiously for any positive sign that there will be an end to the pandemic that has killed more than 1.2 million people worldwide.

“It’s extraordinary,” Dr Anthony S. Fauci, the government’s top infectious disease expert, said on CNN. “It is really a big deal.”

Biden called the development “excellent news” but cautioned that the country was still “facing a very dark winter”. The average daily death toll in the US is inching back towards 1,000, and hospitals nationwide are strained with patients. The President-elect said that Americans would need to rely on basic precautions, like wearing masks, to “get back to normal as fast as possible”.

“It’s clear that this vaccine, even if approved, will not be widely available for many months yet to come,” he said. “The challenge before us right now is still immense and growing.”

The sheer breadth of that challenge was striking on Monday: More than 784,000 cases have been announced in the US over the past week, more than in any other week of the pandemic. The country now averages 900 deaths each day, and 28 states added more cases in the seven-day period ending Sunday than in any other week-long stretch of the pandemic. No states are reporting sustained reductions in cases.

Coronavirus hospitalisations, perhaps the clearest measure of how many people are severely ill, are approaching record levels set during earlier surges of the pandemic, according to data collected by the Covid Tracking Project.

A wave of more than 59,200 patients threatened to overwhelm hospitals in communities across the country on Monday.

The outlook is especially grim in the Midwest and Great Plains, where North Dakota, South Dakota, Iowa, Wisconsin and Nebraska had more new cases per capita over the past week than any others.

New York Times News Service