“Our analyses suggest that the official tally of deaths due to Covid-19 represent a substantial undercount of the true burden,” Dan Weinberger, an epidemiologist at Yale School of Public Health and a lead author of the study, told CNBC. Weinberger said other factors could contribute to the increase in deaths, such as people avoiding emergency treatment for things like heart attacks. However, he doesn’t think that is the main driver.

The study was supported by the National Institute of Health.

The 781,000 total deaths in the United States in the three months through May 30 were about 122,300, or nearly 19% higher, than what would normally be expected, according to the researchers. Of the 122,300 excess deaths, 95,235 were attributed to Covid-19, they said. Most of the rest of the excess deaths, researchers said, were likely related to or directly caused by the coronavirus.