House Speaker Nancy Pelosi called Minority Leader Kevin McCarthy a "moron" Wednesday when asked about his comment that mask mandates for vaccinated people are against the science.

"Make no mistake – The threat of bringing masks back is not a decision based on science, but a decision conjured up by liberal government officials who want to continue to live in a perpetual pandemic state," McCarthy said Tuesday in reaction to new Centers for Disease Control and Prevention (CDC) guidance.

WHERE TO FIND COVID VACCINES

Asked to react to McCarthy's comment Wednesday, Pelosi responded: "He's such a moron." 

Speaker of the House Nancy Pelosi, D-Calif., talks at an event on the urgent need to counter climate change in the US with transformational investments in clean jobs, at the Capitol in Washington, Wednesday, July 28, 2021. (AP Photo/J. Scott Applewhite)

Speaker of the House Nancy Pelosi, D-Calif., talks at an event on the urgent need to counter climate change in the US with transformational investments in clean jobs, at the Capitol in Washington, Wednesday, July 28, 2021. (AP Photo/J. Scott Applewhite) (AP Photo/J. Scott Applewhite)

The Pelosi comment underscores the uniquely hostile relationship between her and McCarthy. Her chief spokesperson even doubled down on the "moron" comment in a subsequent tweet. 

"Unfortunately, we can't verify this audio because of poor quality, but I can confirm that the Speaker believes that saying a mask requirement is ‘not a decision based on science’ is moronic," spokesman Drew Hammill said.

McCarthy responded Wednesday by pointing out what he said are incongruities in the decision to mandate masks, particularly in the Capitol. 

"Well, if she's so brilliant. Can she tell me where the science in the building changes between the House and the Senate?" McCarthy said. "Can she explained to me when the CDC says only vaccinated people need to wear a mask in hotspots … [D.C. is] not with more than 86% of vaccination within here. Can she explain to me the less than 1% affected there. So it’s a lot of questions if she knows so much science explain to me where the science changes in the rotunda."

The Pelosi comment also reflects the strong disagreement over whether the new CDC guidance is wise, especially as the U.S. is trying to motivate more people to get vaccinated. Vaccines have been proven to almost completely eliminate severe illness, hospitalization and death from COVID-19, and also massively reduce transmission of the virus

CDC GUIDANCE FALLOUT: HOUSE, WHITE HOUSE BRING BACK MASK MANDATES

CDC Director Rochelle Walensky announced Tuesday that the agency is now recommending that vaccinated people in areas with high COVID-19 case counts wear masks in indoor public settings. The reasoning behind this, Walensky said, is because "in rare occasions, some vaccinated people infected with the delta variant after vaccination may be contagious and pass the virus to others."

That announcement spurred Capitol Attending Physician Brian Monahan to issue a mask mandate for House of Representatives office buildings and the chamber itself. Pelosi said on Wednesday that Monahan made the decision to mandate masks among House personnel without input from her. 

"That's the purview of the Capitol physician," she said, "a mandate from him. I have nothing to say about that except we honor it with our masks." 

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Monahan, however, was not the only person to issue a mask mandate in the wake of the new CDC guidance. Mandatory mask signage was seen going up in the White House Tuesday.

Nevada Gov. Steve Sisolak, a Democrat, issued a mask mandate for the majority of the counties in the state, based on their rate of viral transmission. And Kansas City, Missouri Mayor Quinton Lucas said Tuesday night that he will be issuing a mask mandate for his city. 

It's likely that many more state, city and county mask mandates are to come in the wake of the new guidance. And it's not clear when such recommendations and orders will be rescinded, whether in the Capitol or anywhere else.