Dr. Fauci says two doses of Pfizer's or Moderna's COVID vaccines are better than one to protect against variants

White House chief medical advisor Dr. Anthony Fauci said that Americans should continue to receive two doses of the Pfizer and Moderna Covid-19 vaccines. A Centers for Disease Control and Prevention study published last week found a single dose of the vaccines was 80% effective in preventing coronavirus infections. But Fauci said he is still concerned about the length of protection after a single dose, especially with the emergence of highly contagious variants.