The organization also plans to analyze how many patients in the study were vaccinated and when, Ms. Gelburd said. More than three-quarters of the patients in the study were infected in 2021, most of them in the last half of the year. On average, four and a half months after infection, patients still experienced prolonged Covid symptoms that qualified for diagnosis.
The results show the potentially staggering impact of long-term Covid on people in their prime and on society as a whole. Nearly 35 percent of patients were aged 36 to 50 years, while nearly one-third were aged 51 to 64 years and 17 percent were aged 23 to 35 years. Children were also diagnosed with the disease after Covid: nearly 4 percent of the patients were aged 12 to 12 years, while almost 7 percent were aged 13 to 22 years.
Six percent of patients were 65 years of age and older, and this proportion most likely reflects the fact that patients enrolled in the regular Medicare program were not included in the study. They were much more likely than younger groups with long-term Covid to have pre-existing chronic conditions.
Analyzed insurance data did not include information about the race or ethnicity of patients, the researchers said.
The analysis, which Ms. Gelburd said was evaluated by an independent scientific reviewer but did not formally pass an expert review, also calculated a risk assessment for patients, a way to assess how likely people are to use health resources. Comparing all insurance claims that patients had up to 90 days before Covid infection, with their claims 30 or more days after infection, the study found that the average risk scores increased for patients in each age group.
Ms. Gelburd and other experts said the results suggest that the effects of long-term Covid are not limited to increased medical costs. They signal “how many people are leaving work, how many are getting disabled, how many are absent from school,” Ms. Gelburd said. “It’s like a pebble thrown into a lake, and this ripple circling over this stone is a concentric circle of impact.”
Because the study only covered the private insured, Dr. Ssentong said, it almost certainly underestimates the scale and severity of long-term covid, especially since low-income communities are disproportionately affected by the virus and often have less access to health care. “I think it could be even worse if we add to the study the population of Medicaid and all these other people that could be missed,” he said.