The lack of clarity on what specifically the agency is basing its judgment on comes as states and cities across the nation are working to vaccinate more of their citizens. And it's making some local officials reluctant to follow the CDC's advice on nearly universal masking.
"While the CDC issued their guidance yesterday at about 3 p.m., they have not yet released their scientific reports on the data that underlies their recommendation," New York City Health and Hospitals President and CEO Mitchell Katz announced at a Wednesday press conference with Mayor Bill de Blasio.
"I think we owe it to New Yorkers to very carefully, as you say, review that information and understand its implications," Katz went on. "Our focus has to be on getting people vaccinated."
"We're assessing the information. What really is important is to assess the research behind it. Which is what our team is doing," de Blasio announced when questioned why the city is lingering any action to mandate mask-wearing for vaccinated folks. "We've got to make sure we understand the ramifications and what makes sense to do."
CDC Director Rochelle Walensky said that the basis for the CDC's reversal on indoor masking for vaccinated people is because "on rare occasions, some vaccinated people infected with the delta variant after vaccination may be contagious and pass the virus to others."
They "may be contagious," Walensky explained, because "the amount of virus" in vaccinated people infected by the delta variant "is pretty similar to the amount of virus in unvaccinated people."
According to the Associated Press, the data to back this claim emerged over the last couple of days from more than 100 samples from several states and one other country. The CDC has not published the information yet, and it is not public.
Rep. Peter Meijer, R-Mich., Wednesday denounced the CDC for its lack of transparency, and the Capitol attending physician for launching a House mask mandate without seeing the CDC's underlying data.
"I think a lot of the frustration is coming with just the blanket absorption of CDC guidance that shifted based upon what they're citing as two unpublished studies that by virtue of being unpublished no one else can look at," he said. Meijer als noted the CDC is citing "a third study from India that was based off of delta transmissibility among individuals who had a non-U.S. vaccine."