Johns Hopkins health policy expert and Fox News contributor Dr. Marty Makary joined "Your World with Neil Cavuto" on Thursday and responded to White House chief medical adviser Dr. Anthony Fauci calling herd immunity an "elusive concept" while acknowledging herd immunity includes those already infected with COVID-19.

MAKARY: My question to Dr. Fauci is how many Americans have natural immunity from prior infection? If so, put that into the formula. The studies show it’s somewhere between a third to 55% of Americans. So it was nice to see that he's acknowledging natural immunity. I hope he changes the description of the formula and the path to normalcy based on that as we hearing from the U.K.  I reached out to Dr. Fauci on Easter. I felt bad for being critical and I wanted to let him know, this is just a different medical opinion in the spirit of an open discussion. It's nothing personal. I respect him. He actually suggested that we're a lot closer on this than some may think or that some of the newspapers have pitted us out to fight about.

I think it's good that he's talking about natural immunity from prior infection now. Because In the past, he clearly did not. I know he told you that he has. Look at the quotes. We have to vaccinate 70 to 85% north to reach herd immunity. He told NPR that, "The New York Times," CNBC. He's been saying it repeatedly. I'm glad he's now changing his tune.

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