Research shows the U.S. had reached what some scientists believed to be “herd immunity” status against Covid-19 last May, with more than 80% of the population immune to Covid either through natural infection or vaccination.
And the actual number of immune Americans may be higher.
That’s because the new study, funded by the Centers or Disease Control (CDC), factored in only 20% of the population as being protected through natural infection after recovering from Covid-19. But over three months ago, CDC estimated the naturally-infected population to be substantially higher: more than 120 million or 36%. And after the spread of Delta variant, and the passage of three more months, experts say the percentage of naturally immune is much higher than the 36% estimate, though CDC has not publicly updated its number in months.
Still, even assuming the study’s lower estimate of naturally immune, and adding in the vaccinated, researchers concluded 83% of the population was immune from Covid-19 as of last May.
One confounding factor is that the vaccines are less effective at preventing Covid infection and spread than hoped.