Dr. Anthony Fauci, left, director of the National Institute of Allergy and Infectious Diseases, confers with Dr. Robert Redfield, director of the Centers for Disease Control and Prevention, at a congressional hearing on March 11.

Dr. Anthony Fauci, left, director of the National Institute of Allergy and Infectious Diseases, confers with Dr. Robert Redfield, director of the Centers for Disease Control and Prevention, at a congressional hearing on March 11.