Seroprevalence increased more rapidly among urgent care than regular care patients. However, by late May it had stabilized at approximately 22 percent in both groups. That’s how the investigators estimate that more than 1.7 million New Yorkers had been infected with the coronavirus by the beginning of the summer.
By that time, 16,674 New Yorkers had died of COVID-19. As a result, the researchers calculate the infection fatality rate (IFR) at about 1 percent.