Criticisms abound for the U.S. Centers for Disease Control and Prevention (CDC) after it changed its mask guidance Thursday to allow vaccinated individuals to go maskless in most settings.

The pivot, days after CDC Director Dr. Rochelle Walensky told a Senate panel it was still not safe to remove masks, is viewed by some experts as hasty.

Walensky told Yahoo Finance Monday that she is aware of all the criticisms, but believes the agency is providing data as it becomes available.

"Quite honestly, what I really need to do is make sure that we are going at the speed of the science. And that's what I told the American people I would do, and that's what I'm doing," she said.

The science, as late as Friday, has begun to show how that the vaccines are working more effectively than previously expected, including against variants, Walensky said.

Walensky emphasized the latest guidance "doesn't say rip off your mask on Friday. It says take the information ... and use it as you think about how you might open your business, your community, your house of worship, and in your school."

And with holidays like Memorial Day weekend coming up, and with them increased travel, the CDC will remain vigilant about variants and potential increases in transmission — which could result in another change in guidance.

"Those are going to be incremental steps. They're going to be at different paces in different communities," Walensky said.

"When we have holidays, people tend to gather. After those gatherings, historically, we've seen some surges.

But with one-third of Americans fully vaccinated, and the data saying vaccinated individuals do not transmit the virus if they do happen to catch it, Walensky is hoping the post-holiday spike is a thing of the past.

Recent drops in cases, deaths and hospitalizations hold promise, and mark a significant turning point in America, she said.

"There's been 16 months where we have been saying you should wear a mask, you should distance, you should protect yourself, you should stay home. This is going to take just as much messaging, if not more, as what is safe as we start to emerge from this," Walensky said.

More from Anjalee:

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• Biden COVID-19 adviser: Vaccine news is great, but we still have a ways to go

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