Based on data from an array of scientific journals, the Center for Evidence-Based Medicine at Oxford University, and the CDC, Just Facts developed a methodology to estimate the number of people who have infectious cases of Covid-19. These calculations show that as of June 27, 2021, roughly 1 of every 988 people in the U.S. has a contagious case of C-19. This is a national average and is not applicable everywhere, but it has improved from about 1 out of 49 people in late-December 2020. This improvement is due to vaccinations and naturally acquired immunity, which have thus far provided lasting protection to the vast bulk of people who previously had C-19 or were vaccinated against it. This outcome is contrary to the claims of scholars and media outlets who said that any immunity to C-19 would quickly fade.