US health officials estimate 20M Americans have had virus

U.S. officials estimate that 20 million Americans have been infected with the coronavirus since it first arrived in the United States, meaning that the vast majority of the population remains susceptible. Thursday's estimate is roughly 10 times as many infections as the 2.3 million cases that have been confirmed. Officials have long known that millions of people were infected without knowing it and that many cases are being missed because of gaps in testing.