Dr. Anthony Fauci is pushing back more pointedly against attacks criticizing his evolving response to the COVID-19 pandemic, Axios reported Sunday.

"The people who are giving the ad hominems are saying, 'Ah, Fauci misled us. First he said no masks, then he said masks,'" Fauci told New York Times columnist Kara Swisher, according to Axios. "Well, let me give you a flash. That's the way science works. You work with the data you have at the time," he said.

"It is essential as a scientist that you evolve your opinion and your recommendations based on the data as it evolves," Fauci said, according to Axios. "And that's the reason why I say people who then criticize me about that are actually criticizing science."

As hospitals experienced a severe shortage of personal protective equipment, or PPE, during the early months of the pandemic, Fauci, head of the National Institute of Allergy and Infectious Diseases, along with the CDC and World Health Organization, initially told people not to wear masks.

But as PPE suppliers ramped up production and data emerged that asymptomatic carriers could spread the virus, Fauci and public health agencies reversed course, with the CDC saying in July that "universal masking" could help the US control the virus in four to eight weeks.

"It was not a change because I felt like flip-flopping. It was a change because the evidence changed, the data changed," Fauci told Swisher, according to Axios, in his latest defense of his position on masks.

Masks have been a political flashpoint for nearly the entire pandemic, while Fauci became a frequent punching bag for former President Donald Trump as well as right-wing media figures who repeatedly downplayed the virus and spread conspiracies and misinformation about everything from the health risks of COVID-19 to Fauci himself.

But Fauci, according to Axios, said he puts "very little weight in the adulation, and very little weight in the craziness of condemning me," and that what has bothered him the most is death threats against him and his family.