WATCH: Biden's reversal on masks has reporter asking 'why should we trust him now?'

The Biden administration has altered their mask requirements in the White House, and their recommendations to states and municipalities across the country, to align with the CDC's new guidance telling vaccinated people to mask-up indoors. When asked about why they've made the changes, they say they are following the science.

What other guidance and recommendations will be reversed in the name of science? This was the question Fox News' Peter Doocy had for Deputy Press Secretary Karine Jean-Pierre on Thursday.

"President Biden said we're not returning to lockdowns, shut downs, and school closures, but he also once said that we didn't have to wear masks anymore once we were vaccinated, so why should Americans trust him now?" Doocy asked.

"Well," Jean-Pierre replied, "because we listen to the scientists, we listen to the experts, this is a public health situation, this is not about politics at all, this is about saving lives, and this is what the president is all about."

"He wants to make sure we are saving lives. If you look at, Peter, the last six months, that's what he's done," Jean-Pierre said. "Every day, and you see that in the numbers. Now we're at a point where we have to double-down and make it very, very clear to people that we can't let the pandemic win, we have to fight."

"So if you're listening to the scientists, if scientists come to you somewhere down the line and say 'it is our opinion that there should be shut downs, and there should be school closures, you would do that?" Doocy asked.

"Well," Jean-Pierre said, "like I said we listen to the CDC and the experts and their guidance, our, y'know, the CDC is a body that is very well respected, and again, we follow their guidance."

Doocy, as are many parents in the United States, was interested to know what that meant in terms of school closures. If the guidance changes, would the administration advocate for closing schools? Many schools, in the United States, along with the nation's largest school districts, closed their doors to students in March 2020, leaving parents fighting to get any kind of education for their kids for well over a year.

"After this new guidance came out, the head of the American Federation of Teachers, Randi Weingarten, came out to say 'we are going to try to open up schools.' Is that good enough for the president?" Doocy asked. "Just trying?"

Jean-Pierre said that both the president, and Secretary of Education Miguel Cardona, want schools open. "They want to see all schools open," she said, and touted the Biden administration's massive, $1.9 trillion spending plan, which was passed in April. The plan had funding for school retrofits and personal protective equipment, among other asks from teachers unions across the country. This was not enough to get many schools open, such as those in Los Angeles.

"There are resources in that plan to make sure that schools are able to open up safely," Jean-Pierre said. She said that PPE and ventilation are what the president "had in mind" when he signed the spending bill.

Doocy wondered, then, why teachers said they were only going to "try. Is that okay?" He asked.

Jean-Pierre said the administration is working with state and local leaders, and that it's "a good sign" that nearly 90 percent of teachers in the US are vaccinated. "Now we just have to make sure we also protect our kids, right, in school, we protect the other administrators at school, people who are immuno-compromised. And that's why the CDC put out that guidance, making sure that people are wearing masks in schools."