have gotten at least one shot of the COVID-19 vaccine so far, but researchers warn that vaccine refusal may keep the country from reaching herd immunity.

have gotten at least one shot of the COVID-19 vaccine so far, but researchers warn that vaccine refusal may keep the country from reaching herd immunity.

She believes some people are having "life-threatening reactions" to the vaccine that the media aren't reporting.

"Vaccine hesitancy is a big problem for all of us," says Ali Mokdad, who tracks coronavirus trends at the Institute for Health Metrics and Evaluation at the University of Washington.

Up until now, the nationwide vaccine campaign has seen demand outstrip supply, but Mokdad says he believes that will soon change.

By May, he believes, "We will have more vaccines than people willing to take the vaccine.".

NPR/Marist's polling has seen the number of people saying they would refuse a vaccine drop since the question was first asked in August, and it continues to fall.

"What most of us want is a safe return to something that looks more normal," says Samuel Scarpino, who models the coronavirus outbreak at Northeastern University.

(The Centers for Disease Control and Prevention recommends people who already had an infection to get vaccinated anyway, so many COVID-19 survivors will also be in the "yes" camp.).

But based on current polling data, Scarpino says that the tipping point for herd immunity for the virus remains out of reach: "We can't get there right now.".

"It's very hard to convince people to take the vaccine in summer, when everything is going good," Mokdad says.

Scarpino says he believes that more contagious variants such as the one first reported in the U.K.

But the number of people saying no is relatively high across racial groups, economic classes and geographic regions

"You need to speak to these different groups: the minority groups, the Republicans and the other people who feel like they have some distrust in science," she says

and elsewhere," Mokdad says