ANALYSIS/OPINION:
The pandemic will be over when the U.S. reaches herd immunity. Herd immunity is the level of individual immunity where the spread of the disease from person to person becomes unlikely, and results in the whole community becoming protected, even those who are not immune.
Herd immunity is a function of the rate at which the virus spreads from person to person. For COVID-19, credible estimates are that each infected person infects another 2.3 people, which if true means that herd immunity is reached when 56.5% of the population is immune. We will reach that in the U.S. when the number of people who have the virus (whether they know it or not), plus the number of people who are naturally immune, plus the number who have been vaccinated equals 185 million.