In an interview Friday, CNN asked Fauci whether a vaccine with 70% to 75% efficacy taken by only two-thirds of the population would provide herd immunity to the coronavirus. Herd immunity is when a sufficient proportion of a population is immune to an infectious disease, either through prior illness or vaccination, so that spread from person to person unlikely. "The fact that you got infected means that it's likely that you'll infect someone else who might infect someone else who then will infect a vulnerable person," Fauci said. When asked how the United States is doing with contact tracing, Fauci answered, "I don't think we're doing very well." "If you go into the community and call up and say, 'how's the contact tracing going?'

Source: CNN June 29, 2020 00:11 UTC