Fauci has led the National Institute of Allergy and Infectious Diseases for 36 years, through several viral epidemics including HIV/AIDS, SARS, Zika and Ebola. Now, he's tackling COVID-19. WATCH NIGHTLINE EPISODES: https://abc.go.com/shows/nightline ALSO AVAILABLE ON HULU: https://hulu.tv/2wSmSrZ BREAKING NEWS UPDATES: https://abcnews.go.com/Health/Coronavirus SUBSCRIBE to ABC NEWS: https://bit.ly/2vZb6yP Watch More on http://abcnews.go.com/ LIKE ABC News on FACEBOOK https://www.facebook.com/abcnews FOLLOW ABC News on TWITTER: https://twitter.com/abc #Nightline #Fauci #Coronavirus #COVID19 #Pandemic #Health #Trump #WhiteHouse #CDC #Doctor #ABCNews