The comparison, published online in the medical journal JAMA Network Open, found that the number of deaths from all causes was roughly equal during the two peak months of the flu epidemic and the first 61 days of the current outbreak.

The H1N1 flu pandemic eventually killed 50 million people a century ago, about 675,000 of them in the United States. The current pandemic has claimed at least 746,000 lives worldwide, about 162,000 of them in the United States, according to a tally kept by The Washington Post.

“For anyone who doesn’t understand the magnitude of what we’re living through, this pandemic is comparable in its effect on mortality to what everyone agrees is the previous worst pandemic,” said Jeremy Faust, an emergency physician at Brigham and Women’s Hospital in Boston who led the team that conducted the data review.