The Food and Drug Administration also gave an OK to boosters that differ from the vaccine originally used to immunize people against COVID-19. A mix-and-match approach could ease the booster rollout.

It's the first step in an audacious plan to solve vaccine inequity by setting up the manufacturing of mRNA vaccines across low-resource countries,

"I knew I had wanted to do something with light because I felt like it's just been such a dark year and a half that I wanted to bring light to whatever it was I was doing," Laura Weiss told NPR.

A source familiar with the discussions says administration health experts could make the recommendation for fully vaccinated adults as soon as this week.

The delta variant is the fast-moving strain of the coronavirus now found in 96 countries. It's expected to be the dominant variant in the U.S. within weeks.

Oxford-AstraZeneca promised its COVID-19 vaccine would be effective, cheap and available worldwide. Five months after its launch, the path forward has been anything but smooth.

One of the hottest areas of research right now: studies to determine how well current vaccines work against emerging coronavirus "variants of concern."

Moderna has begun testing its vaccine on children as young as 6 months old. A principal investigator in the trial says getting children vaccinated would be "a step getting back to our normal life."

Pfizer and Moderna each agreed to supply 100 million doses of COVID-19 vaccine to the U.S. by the end of March. With just under three weeks left, both companies have their work cut out for them.

As the new Johnson & Johnson COVID-19 vaccine rolls out, the health care community is trying to ward off misconceptions about it. The vaccine's one-shot feature may be what wins many over.

Many of the coronavirus vaccines like it cold. Really cold. Sub-zero cold. Why is this the case? And how is the world handling this frigid requirement?

In a new round of tests, the drug company wants to see if booster doses of its vaccine will ramp up defenses against emerging strains of the coronavirus.

The two companies making COVID-19 vaccines each promised to deliver 100 million doses to the federal government by the end of March. So far, they appear to be running behind.

NPR's Bob Mondello is back from his vaccination appointment and feeling safer.

Agency officials said reducing the number of doses creates a potential for harm in patients because "they may assume that they are fully protected when they are not" and may "take unnecessary risks."