As the coronavirus continues to spread in the U.S., millions of Americans are asking when they'll see daily life return to normal again.

Public spaces are closed, a majority of the country is under stay-at-home orders and handshakes seem like a thing of the past. Last week the Centers for Disease Control (CDC) changed their guidance on face masks: At first, people were advised not to wear masks in public; now, the CDC and other health experts say they can be a vital part of slowing the spread of the virus.

Experts say that even when daily life returns to normal, it's likely Americans and others around the world will still be wearing masks.

Experts suggest that even as daily life begins to return to normal, people may have to continue to wear masks until a vaccine is developed and deployed. Jamie Squire / Getty Images

In an interview with AccuWeather, Shan Soe-Lin, a lecturer in global affairs at Yale University in New Haven, Connecticut, said that people "are going to have to wear masks until there's a vaccine."

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In an interview with TODAY, Soe-Lin, an immunologist by training, elaborated on her comments.

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"I think that you're going to need to wear masks for as long as COVID is a threat, and COVID is going to be a threat until you have a vaccine," Soe-Lin said. "If you read different plans for re-opening the economy, the plan is to really put a chokehold on (the virus) and only open the economy when the number of cases has fallen to a level that the hospitals can manage ... but masks would still be an important thing to cut down on transmission until you have a vaccine."

Soe-Lin also said that masks can be worn by almost anyone in the population, making them an easy way to try to prevent the spread of the virus.

"Masks are one of the most equitable interventions we have," Soe-Lin said. "We know not everyone can socially distance, but everyone can cover their face."

Saad Omer, the director of the Yale Institute for Global Health, agreed with Soe-Lin's assessment of the situation, and said that masks might be needed for an even longer period of time as a vaccine is deployed, a process that could take more than a year.

"Even when a vaccine becomes available, the measures will outlast the release of the vaccine," said Omer, who is also a professor at the Yale School of Medicine and teaches about infectious diseases. "We are in uncharted territory right now. Vaccines will vary by country, by mode of delivery ... You’re looking at least a year to deploy the vaccine and have enough coverage."

Omer also said it's likely people would wear masks for a significant period of time because they are "easy to implement" and have a "low social cost."

"Obviously, the guidance has changed ... but generally speaking, things that don't have a huge social cost will likely be one of the last things to go," said Omer, who added that he hoped people didn't see the new guidance as a "license to hoard" supplies. "Compared to other things, like closing businesses and cancelling schools, they have a low cost (to society)."

In early March, Soe-Lin co-published an article in the Boston Globe, which called on people to start wearing masks or cloth face coverings.

Soe-Lin said that while N-95 and surgical masks should be reserved for first responders and medical workers, wearing a cloth mask is "better than nothing" and can help slow the spread of viruses like the coronavirus and influenza.

"Masks and face coverings can be helpful, especially in a pandemic situation," Soe-Lin said. "They're not useful enough, in a normal flu season, to ask people to wear them, but we're not in a normal flu season right now."

While cloth masks can be effective, Soe-Lin pointed out that it is important to treat them properly: People should only wear a mask out once, without touching or removing it, and wash the masks after each use. Different fabrics can also be more effective.

"Multi-layered masks are more effective than single layers," Soe-Lin explained. "Bandanas, I think, should be the mask material of last resort, they're just too thin ... A cloth mask will trap a significant percentage of the virus inside the mask."