As 21 states report a rise in new Covid-19 cases, CDC chief says more than 90% of Americans remain susceptible

Dr. Anthony Fauci said Thursday that even an effective Covid-19 vaccine won't replace the need for other public health measures, such as wearing a mask, social distancing and washing hands. Fauci, the director of the National Institute of Allergy and Infectious Diseases, said the vaccine will not be 100% effective and taken by 100% of the population -- which means there still will be room for Covid-19 to spread. Fauci said he's being 'practical' when he says, 'I think if we can get 75 to 80% of the population vaccinated, I think that would be a really good accomplishment.' 'It is not going to eliminate the need to be prudent and careful with our public health measures,' he said in a Facebook Live conversation with New Jersey Gov. Phil Murphy.