People who survived Covid-19 early in the pandemic, before there were vaccines, continued to be at higher risk for a slew of health problems for up to two years after they got over their initial infections, compared to others who didn’t test positive, a new study finds, and that was especially true if they were hospitalized.
These health problems include heart problems, blood clots, diabetes, neurologic complications, fatigue and difficulties with mental health and have come to be known collectively as long Covid.
When researchers tallied the risks for more than 80 different complications that are associated with long Covid, they translated the collective toll into a metric called a disability adjusted life year, or DALY. Each DALY represents one year of healthy life lost to illness. They found that long Covid generated more than 80 disability-adjusted life years, or DALYs, for every 1,000 people who weren’t hospitalized for their initial infection.
That means long Covid creates a higher burden of disability than either heart disease or cancer, which cause about 52 and 50 DALYs for every 1,000 Americans, respectively, according to the Institute for Health Metrics and Evaluation’s Global Burden of Disease study.
“When I looked at that initially, I was really shocked,” said study author Dr. Ziyad Al-Aly, who is director of the clinical epidemiology center at the Veterans Affairs St. Louis Health Care System. “That’s actually a huge number.
“We did the analyses multiple times and, and then it just always can come back to be to be the same.”
After considering their findings, though, Al-Aly said it really shouldn’t be such a huge surprise that long Covid is so disabling, because it affects so many different parts of the body.
“I think that we need to understand that infections lead to chronic disease and we need to take infection seriously,” even when it seems to be mild, Al-Aly said.
The study, which was published Monday in the journal Nature Medicine, looked at the medical records of nearly 140,000 veterans who survived for 30 days after getting a Covid-19 infection in 2020, and compared their health outcomes to nearly 6 million other patients in the VA health system who had no evidence of infection.
The study has some important caveats. On average, people in the VA health system are older, in their 60s, and around 90% were male, so the findings may not translate to those who are younger or to women.
None of the people in the study were vaccinated at the time they were infected because the vaccines had not been developed yet, and there weren’t yet antiviral treatments targeted to Covid-19. Studies have since shown that vaccination and early treatment can help curb long covid risk.
The researchers only included people in the Covid-19 infection group if they had a positive test, but tests were slow to roll out early in the pandemic, and the researchers say many people may have had the infection with no test results recorded in their medical records. That may have resulted in some people being included in the control group when they should have been in the infection group. If that was a large number of people, the study authors say, their results may be an underestimation of the true risks people faced post-infection.
Al-Aly said he used this group because he wanted to learn more about the long-term outcomes for people who get Covid-19, and he needed to find patients who were more than two years past their infections, so these risks may have gone down over time as vaccines and better treatments were developed.
Still, the study paints a sobering picture of how long people faced physical consequences from early infections.
The study found people who were not hospitalized with Covid-19, still had an elevated risk of death for about six months after they first got sick.
And over the next two years, patients’ risks of having many long Covid symptoms went down, but it remained elevated for about one-third of the 77 ailments that were studied. Some of those lingering problems included blood clots, a slower than normal heartbeat, fatigue, diabetes, gastrointestinal problems, sleep problems, muscle and joint pain, headache, hearing and smell loss, and autonomic nervous system dysfunction.
Experts who were not involved in the researcher praised the study’s size and detail.
“I think it’s really interesting that they found that even two years out, there’s significant health issues still experienced by those that COVID infection compared to those who did not. That’s a key aspect,” said Dr. Linda Geng, who is co-director of the Stanford post-acute Covid-19 Syndrome Clinic.
People in the group who had to be treated in the hospital for an initial Covid-19 infection fared even worse. They remained at increased risk for death and hospitalization for at least two years after they recovered from their acute symptoms.
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Out of 77 different long Covid issues studied, people who were hospitalized remained at elevated risk for about two-thirds of them even two years later. These included heart problems, stomach problems, memory and thinking difficulties, blood clots, diabetes and lung problems. They were also more likely to have a substance use disorder, including for alcohol and opioids. They were also more likely to report contemplating suicide.
Geng says the study’s findings mirror what she sees in her clinic, as she treats long Covid-19 patients.
She says long Covid is such a broad, mixed bag of problems that individuals need to realize that the conclusions of the study might not apply to their own situation.
“A lot of people do get better,” Geng said. “There are some people who may have had symptoms for a few weeks, and will get better over that three month time period. And then there are other people within the three to six month time period. It’s a spectrum, right?”
Where a person falls on that spectrum will depend on their age, underlying health before Covid-19, their vaccination status, and whether they took antivirals early in their infection, Geng said.
Bryan Lau, an epidemiologist at the Johns Hopkins Bloomberg School of Public Health who is working with the University’s Covid Long study, praised the study for wrangling massive amounts of data, but he points out that because the researchers were relying on electronic medical records for their data, they weren’t able to actually talk to patients to dig into any of the trends they were seeing.
“They did look at DALYs, which, you know, which is a measure of sort of how much disability is, in this population. But it’s also quite different than asking somebody you know, Can you climb a flight of stairs? Or can you walk a quarter of a mile, and getting that data,” said Lau, who was not involved in the research.
And finally, as good as the study is, Lau said, he says it’s smart to remember that in medical research the truth is usually in the accumulation of evidence over time and not in any single study.
“I take everything with a little bit of grain of salt, if you will, until other studies can come along,” he said.