04:27 - Source: CNN
Dr. Fauci explains why his herd immunity estimate has shifted
CNN  — 

Just a week after Sen. Marco Rubio was criticized for getting the coronavirus vaccine ahead of some front-line workers, the Florida Republican is back in the hot seat for his comments accusing Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, and others of manipulating public perception surrounding Covid-19.

“Dr. Fauci lied about masks in March,” Rubio tweeted on Sunday morning. “Dr. Fauci has been distorting the level of vaccination needed for herd immunity.”

Facts First: Rubio’s claims are false and misleading. Fauci did not lie about masks. Though Fauci, along with several other US health leaders, did initially advise people not to wear masks, his guidance evolved along with the scientific community’s understanding of the coronavirus. Similarly, Fauci has insisted any change in the numbers he’s provided regarding herd immunity is due in part to new science, not just polling, and representative of the fact that there’s a range of estimates for the necessary level.

On vaccines

There is some basis for Rubio’s claim on Fauci’s stance on herd immunity levels. Last week, The New York Times reported that Fauci acknowledged he was “slowly but deliberately” raising his estimates for the level of vaccination needed to reach herd immunity.

According to the article, Fauci said, “When polls said only about half of all Americans would take a vaccine, I was saying herd immunity would take 70 to 75%. Then, when newer surveys said 60% or more would take it, I thought, ‘I can nudge this up a bit,’ so I went to 80, 85.” But even in his interview with The New York Times, Fauci shied away from a definitive number and reiterated that there’s a range of possibilities.

Fauci clarified his stance in an interview with CNN’s Dana Bash on “State of the Union” Sunday that aired more than an hour before Rubio tweeted.

Asked whether polling had influenced his varying estimates, Fauci said, “No, I mean, it’s a bit of that.”

When asked why he wasn’t straightforward to begin with about the higher level of vaccinated population necessary to achieve herd immunity, Fauci pushed back on the idea that he had used certain data points to distort people’s perception. “I don’t think it can be interpreted as being straight or not,” he said, adding that “these are pure estimates,” and later that “nobody really knows for sure.”

Fauci explained that he was not primarily basing his recommendation on polling about public perception of the vaccine but that his higher estimates were influenced by the highly transmissible measles, which needs at least 90% of the population vaccinated to maintain herd immunity.

“That’s not a big leap to go from 75 to 85. It was based on calculations and pure extrapolations from measles,” Fauci said. He noted the range for the coronavirus is likely less than 90% because the coronavirus is less transmissible than measles.

On masks

Fauci told CNN’s Chief Medical Correspondent Dr. Sanjay Gupta during a CITIZEN by CNN Conference that his evolving advice about masks is a “classic example” of how guidance can change as additional scientific evidence emerges. The pandemic, he said, is an “evolving situation.”

In March, the World Health Organization, the CDC and Fauci said face masks should be reserved for those who are sick or caring for the sick, with Fauci even telling 60 Minutes there was “no reason” for people in the US to be walking around with a mask. However, all three later reversed their guidance after doctors learned more about how the coronavirus spreads.

In June, speaking to The Street, Fauci said the reason he had previously advised people against wearing masks was that “we were concerned the public health community, and many people were saying this, were concerned that it was at a time when personal protective equipment, including the N95 masks and the surgical masks, were in very short supply.”

At the CITIZEN by CNN Conference in September, Fauci further explained that in the spring, “we were not aware that 40 to 45% of people were asymptomatic, nor were we aware that a substantial proportion of people who get infected get infected from people who are without symptoms.” Once that became clear from the data, Fauci said, “that makes it overwhelmingly important for everyone to wear a mask.”

“So when people say, ‘Well, why did you change your stance? And why are you emphasizing masks so much now when back then you didn’t – and in fact you even said you shouldn’t because there was a shortage of masks?’ Well, the data now are very, very clear,” Fauci said.

UPDATE: This article has been updated to reflect Fauci’s past comments on masks and current position on herd immunity.