Risk of death from COVID-19 lessens, but infection still can cause issues three years later
New findings on long COVID — long-term effects on health experienced by many who have had COVID-19 — present a good-news, bad-news situation, according to a study at Washington University School of Medicine in St. Louis and the Veterans Affairs St. Louis Health Care system.
The bad news: COVID-19 patients who were hospitalized within the first 30 days after infection face a 29% higher risk of death in the third year compared with people who have not had the virus. However, the three-year death risk still marks a significant decline compared with such risk at the one- and two-year marks post-infection. The findings also show that even people with mild COVID-19 were still experiencing new health problems related to the infection three years later.
The good news: The increased risk of death diminishes significantly one year after a SARS-CoV-2 infection among people who were not hospitalized for the virus. This demographic accounts for most people who have had COVID-19.
The new research, published May 30 in Nature Medicine, tracked the virus’s health effects in people three years after being infected with the original strain of COVID-19 in 2020. That year, about 20 million people tested positive for the virus in the U.S. The new study assessed the risk of death and 80 adverse health conditions in people three years after being diagnosed with COVID-19.
Up to 10% of people infected with the virus experience long COVID, according to federal data.
The team analyzed millions of de-identified medical records in a database maintained by the U.S. Department of Veterans Affairs, the nation’s largest integrated healthcare system. The study included more than 114,000 veterans with mild COVID-19 who did not require hospitalization; more than 20,000 hospitalized COVID-19 patients; and 5.2 million veterans with no COVID-19 diagnosis. Patients were enrolled in the study from March 1, 2020, to Dec. 31, 2020, and followed for at least three years, until Dec. 31, 2023. Patients included people of diverse ages, races and sexes; statistical modeling ensured parity in representation.
In the third year after infection, COVID-19 patients who had been hospitalized experienced a 34% elevated health risk across all organ systems compared with people who did not have COVID. That number is down from a 182% increased risk one year after a COVID infection and a 57% risk two years after.
Among nonhospitalized patients, researchers found a 5% increased risk in suffering from long COVID in the third year after infection. This translates into 41 more health problems per 1,000 persons – a small but not trivial burden. The long-term health effects in the third year primarily affected the GI, pulmonary and neurological systems. By comparison, the risk was increased by 23% one year after infection and increased by 16% two years after.
In the analysis, researchers also measured and compared the number of healthy life-years lost due to COVID-19. They found that among the nonhospitalized, at three years after infection, COVID-19 had contributed to 10 lost years of healthy life per 1,000 persons. By comparison, three years post-infection, those hospitalized for COVID-19 had experienced 90 lost years of healthy life per 1,000 persons.
