• The 781,000 total deaths in the U.S. in the three months through May 30 were nearly 19% higher than what would normally be expected, the study said.
  
  
• The number of excess deaths from any causes were 28% higher than the official tally of U.S. Covid-19 deaths during those months.

Researchers found that the excess number of deaths over normal levels also exceeded those attributed to Covid-19, leading them to conclude that many of those fatalities were likely caused by the coronavirus but not confirmed. State reporting discrepancies and a sharp increase in U.S. deaths amid a pandemic suggest the number of Covid-19 fatalities is undercounted, they said.

“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.

In a large-scale retrospective analysis of 2,541 patients hospitalized between March 10 and May 2, 2020 across the system’s six hospitals, the study found 13% of those treated with hydroxychloroquine alone died compared to 26.4% not treated with hydroxychloroquine. None of the patients had documented serious heart abnormalities; however, patients were monitored for a heart condition routinely pointed to as a reason to avoid the drug as a treatment for COVID-19.