Alex Edelman / AFP via Getty Images Dr. Anthony Fauci said that it could take up to 90% of the US population to get vaccinated to reach herd immunity against the coronavirus. "We really don't know what the real number is," Fauci said in an interview with The New York Times. "I think the real range is somewhere between 70 to 90 percent. But, I'm not going to say 90 percent." This month, the US Food and Drug Administration authorized both Moderna and Pfizer and BioNTech's coronavirus vaccine for emergency use which have been rolled out across the country.