By Nov. 15 of last year, roughly 47 million Americans -- about 14.5% of the U.S. population -- had already been infected with the new coronavirus, a new study finds. That's much higher than the close to 11 million known U.S. cases of infection that were recorded by that date, the researchers said, because reported cases "do not represent the full SARS-CoV-2 disease burden." … "Findings of this study suggest that although more than 14% of the U.S. population was infected with SARS-CoV-2 by mid-November, a substantial gap remains before herd immunity can be reached," they reported Jan. 5 in JAMA Network Open.