How many Covid-19 tests have been done in the US?

Last week president Donald Trump explained his three-phase plan to reopen the economy in May and end the quarantine period. Some governors are on the same page as Trump and are considering easing social distancing restrictions, but new estimates by researchers at Harvard University suggest that the United States cannot safely reopen unless it conducts more than three times the number of coronavirus tests it is currently administering over the next month.

An average of 146,000 people per day have been tested for the coronavirus nationally so far this month, according to the Covid Tracking Project, which on Friday reported 3.6 million total tests across the country. To reopen the United States by mid-May, the number of daily tests performed between now and then should be 500,000 to 700,000, according to the Harvard estimates.

“If you have a very high positive rate, it means that there are probably a good number of people out there who have the disease who you haven’t tested,” said Ashish Jha, the director of the Harvard Global Health Institute. “You want to drive the positive rate down, because the fundamental element of keeping our economy open is making sure you’re identifying as many infected people as possible and isolating them.”

The researchers said that expanded testing could reduce the rate to 10 percent, which is the maximum rate recommended by the World Health Organization. In Germany, that number is 7 percent, and in South Korea, it is closer to 3 percent.

There is variation in the rate of testing and positive results among states, but most need to administer more tests to get to the level the researchers suggest a minimum of about 152 tests per 100,000 people each day.