We’ll Have Herd Immunity by April – Wall Street Journal

Amid the dire Covid warnings, one crucial fact has been largely ignored: Cases are down 77% over the past six weeks. If a medication slashed cases by 77%, we’d call it a miracle pill. Why is the number of cases plummeting much faster than experts predicted?

In large part because natural immunity from prior infection is far more common than can be measured by testing. Testing has been capturing only from 10% to 25% of infections, depending on when during the pandemic someone got the virus. Applying a time-weighted case capture average of 1 in 6.5 to the cumulative 28 million confirmed cases would mean about 55% of Americans have natural immunity.

…explained only by natural immunity. Behavior didn’t suddenly improve over the holidays; Americans traveled more over Christmas than they had since March. Vaccines also don’t explain the steep decline in January. Vaccination rates were low and they take weeks to kick in.