Mayor Bill de Blasio’s chief medical adviser on Feb. 25 downplayed the results of two studies suggesting that a new coronavirus variant found in New York City in November will be more resistant to vaccines now being administered.

California surpassed New York on Feb. 9 as the U.S. state with the most coronavirus deaths, a grim reminder of the pandemic’s toll even as the vaccine rollout and a sharp drop in new cases buoyed hopes of life eventually returning to normal.

The United States reported a 25% drop in new cases of Covid-19 to about 825,000 during the week ended Feb. 7, the biggest fall since the pandemic started, although health officials said they were worried new variants of the virus could slow or reverse this progress.

California-based Amgen is in the process of eliminating hundreds of U.S. jobs, the majority of which are centered on the company’s sales team, according to a recent sales call.

Severe Covid-19 infections are beginning to abate in many parts of the United States even as the death toll mounts, signaling an end to the pandemic’s post-holiday surge and prompting some states to ease public health restrictions.

The United States reported a 21% drop in new cases of Covid-19 for the week ended Jan. 24, as all but one state reported declines in new infections, and the number of coronavirus patients in hospitals also fell.

The U.S. coronavirus death toll topped 400,000 on Jan. 19, according to a Reuters tally, as the country hardest hit by the pandemic struggled to meet the demand for vaccines to stem the spread of infection.

Moderna Inc. received a report from California’s health department that several people at a center in San Diego were treated for possible allergic reactions to the company’s Covid-19 vaccine from a particular batch.

The United States lost more than 23,000 lives to Covid-19 during the week ended Jan. 17, setting a record for the third week in a row, though the number of new infections and the amount of patients in hospitals both fell from the previous seven days.

More than 10 million Americans had received their first dose of a Covid-19 vaccine as of Jan. 13, according to the U.S. Centers for Disease Control and Prevention, as the year-old pandemic roared on unchecked.