ROB SCHMITZ, HOST:
Long COVID has killed more than 3,000 people in the United States. That's according to the federal government's first tally of deaths caused by long-term complications of COVID-19. But as NPR's health correspondent Rob Stein reports, that's probably a significant undercount.
ROB STEIN, BYLINE: COVID-19 has killed more than 1 million people in the U.S. and left many others suffering from brain fog, fatigue and other often debilitating long-term health problems. So Farida Ahmad and her colleagues at the National Center for Health Statistics wanted to see how often long COVID itself was being cited as a cause of death.
FARIDA AHMAD: As long COVID is becoming more of an issue in terms of health and illness, we wanted to see if that's something that was manifesting in death, if long COVID was causing deaths.
STEIN: So the researchers scoured death certificates for any mention of long COVID. They found more than 3,500 deaths where doctors specifically cited long COVID. Many were among people with heart disease, lung disease and other conditions that may have been worsened by long COVID.
AHMAD: It can affect more than just the brain fog, but it can affect other organs as well.
STEIN: And the number of deaths blamed on long COVID appears to be increasing.
AHMAD: Over time, we're seeing more long COVID deaths increase. And as it's become more recognized and more diagnosed, I think we'll see more of it showing up in medical records and death certificates.
STEIN: Other researchers say the true number of deaths from long COVID is in all likelihood already much higher.
HARLAN KRUMHOLZ: This number represents the tip of the iceberg. The floor for the estimate, it's no doubt higher than this.
STEIN: Dr. Harlan Krumholz studies long COVID at Yale.
KRUMHOLZ: There are a whole bunch of other people that most doctors don't even know how you would put that in the death certificate right now. They don't even know how to document long COVID on the death certificate.
STEIN: And the toll from long COVID will likely continue to climb as the nation faces yet another surge of infections.
Rob Stein, NPR News. Transcript provided by NPR, Copyright NPR.