Reuters reported that AstraZeneca sold off the U.K. pharma giant’s 7.7 percent stake in the Covid-19 vaccine manufacturer Moderna for more than $1 billion.

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.

The first big real-world study of the Pfizer/BioNTech vaccine to be independently reviewed shows the shot is highly effective at preventing Covid-19, in a potentially landmark moment for countries desperate to end lockdowns and reopen economies.

Deaths from Covid-19 in the United States fell for a third straight week during the week ended Feb. 21, as cases and hospitalizations showed steep drops.

The United States on Feb. 22 crossed the staggering milestone of 500,000 Covid-19 deaths just over a year since the coronavirus pandemic claimed its first known victim in Santa Clara County, California.

Drug developer Novavax Inc. completed enrolling 30,000 volunteers in a late-stage study of the company’s Covid-19 vaccine in the United States and Mexico.

The United States reported a 23% drop in new cases of Covid-19 and a 16% fall in the number of people hospitalized with the virus for the week ended Feb. 14, with both figures declining for a fifth week in a row.

A Covid-19 vaccine candidate developed by Sanofi and U.S. group Translate Bio “will not be ready this year,” the French drugmaker’s chief executive told Le Journal du Dimanche newspaper.

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.

Moderna Inc. proposed filling vials with additional doses of the Covid-19 vaccine to ease a crunch in manufacturing as the company approaches the manufacturing of almost a million doses a day.