Jen Psaki crumples when Fox News reporter grills her about face masks for vaccinated people

White House press secretary Jen Psaki crumpled under questioning Tuesday over new mask guidance from the Centers for Disease Control and Prevention, resorting to justifying the new guidance as a "determination" from "public health officials" without pointing to data or evidence.

What is the background?

The CDC released updated guidance Tuesday that fully vaccinated Americans living in regions with high transmission of COVID-19 should mask up.

Previously, CDC guidance stated that fully vaccinated individuals should "resume activities that you did prior to the pandemic ... without wearing a mask or physically distancing."

What was Psaki asked?

During Tuesday's press briefing at the White House, Fox News reporter Peter Doocy asked Psaki why the Biden administration is recommending some fully vaccinated Americans wear face masks if the COVID-19 vaccines are effective.

The implication, of course, is that by re-enacting face mask guidelines, administration officials may be sowing distrust in the vaccines.

"If it's a pandemic of the unvaccinated, still, then why do vaccinated people need to put the masks back on?" Doocy asked.

In response, Psaki affirmed Doocy's thesis — that unvaccinated people are driving up COVID-19 cases, which makes the mask guidance for fully vaccinated individuals confusing — but did not address his question.

"Well, Peter, first of all, I would say again— just to go back to this chart, which I will handily point to again: If you are vaccinated, if you are vaccinated, your life— it can save your life. And I think the clear data shows that this pandemic is killing, is hospitalizing, is making people very sick who are not vaccinated. That still continues to be the case, regardless of what the mask guidance looks like," Psaki said.

Doocy asked again, "But if the vaccines work, which this sign says that they do, then why do people who had the vaccine need to now wear masks — the same as people who have not had it?"

This time Psaki essentially deflected to "because we said so."

"Because the public health leaders in our administration have made the determination, based on data, that that is a way to make sure they're protected, their loved ones are protected," she told Doocy. "And that's an extra step, given the transmissibility of the virus, that people — that they're advising people to take."

Is there a better answer?

CDC Director Dr. Rochelle Walensky provided a better explanation Tuesday as to why the CDC is — yet again — reversing course.

While she reaffirmed the overwhelming majority of COVID-19 cases are among the unvaccinated, she explained that studies show vaccinated people carry a significant viral load of COVID-19 variant in their nose and airway, enough to infect other people.

From the Associated Press:

Most new infections in the U.S. continue to be among unvaccinated people. So-called breakthrough infections, which generally cause milder illness, can occur in vaccinated people. When earlier strains of the virus predominated, infected vaccinated people were found to have low levels of virus and were deemed unlikely to spread the virus much, CDC Director Dr. Rochelle Walensky said.

But with the delta variant, a mutated and more transmissible version of the virus, the level of virus in infected vaccinated people is "indistinguishable" from the level of virus in the noses and throats of unvaccinated people, Walensky said.

The face masks are intended to stop that transmission, Walensky explained.