Nearly one-third of the entire U.S. population had been infected with COVID-19 by the end of 2020 — a much higher rate of infection than previously known, researchers reported in the journal Nature this week

Source: One third of Americans were infected with COVID-19 by end of 2020, Columbia University study finds –

Which means this pandemic is just like many past pandemics and our mitigations measures had little effect. Another study says 55% of residents of some Southern California counties had antibodies by end of January 2021.