ANN ARBOR – People who become severely ill from COVID-19 are more likely to experience persistent symptoms, according to a new study by the University of Michigan.
Individuals who experience lingering symptoms long after their infection are known as long-haulers, and the findings underscore the critical need to identify and treat these patients.
Common long-haul symptoms, also referred to as post-acute sequelae of SARS-CoV-2 infection (PASC) include shortness of breath, extreme fatigue and continuous loss of smell or taste.
“While we’re in the midst of trying to stop the spread of the pandemic, we need to develop formal, coordinated surveillance of long-term symptoms to better understand this syndrome and provide guidance for clinical management,” lead author of the study and research investigator in the Center for Social Epidemiology and Population Health at the U-M School of Public Health, Jana Hirschtick, said in a release.
Hirschtick and her team found that 53 percent of individuals who contracted COVID were still symptomatic 30 days after initial symptoms arose. Thirty-five percent of those still had symptoms 60 days post-onset.
The research team used the Michigan COVID-19 Recovery Surveillance Study, which is based on adults 18 and older with a confirmed PCR COVID test in the Michigan Disease Surveillance System. A total of 629 individuals completed surveys from a random sample of 2,000 cases who met the study’s inclusion criteria.
In order to be eligible for the study, the adults had to have COVID onset on or before April 15, 2020. The participants lived in Macomb, Oakland, St. Claire, Monroe, Washtenaw and Wayne counties.
For the survey, participants included hospitalization status, self-reported symptom severity and sociodemographic and clinical information.
Of the final study samples, 56 percent of participants were female, 68 percent were age 45 and older, 46 percent were non-Hispanic white and 35 percent were Black.
According to U-M, of the respondents:
- 53% reported symptoms at 30 days and 35% reported symptoms at 60 days.
- Respondents reporting very severe (vs. mild) symptoms had 2.25 times higher prevalence of symptoms at 30 days and 1.71 times higher prevalence of symptoms at 60 days.
- Hospitalized (vs. nonhospitalized) respondents had about 40% higher prevalence of symptoms at 30 and 60 days.
- Although persistent symptoms were more prevalent among older respondents and those with severe disease, 21% of 18-to-34-year-olds and 25% of respondents reporting mild illness still had symptoms 60 days after their COVID-19 onset.
- Older age, lower income, self-reported severe or very severe (vs. mild) symptoms and hospitalization statistically significantly predicted 30-day COVID-19, while having a diagnosed psychological disorder, very severe symptoms and hospitalization statistically significantly predicted 60-day COVID-19.
“Our data suggest a significant proportion of people with COVID-19 will continue to experience symptoms, even among people with relatively mild initial illness,” associate professor of epidemiology and principal investigator of the Michigan COVID-19 Recovery Surveillance Study, Nancy Fleischer, said in a release.
Due to a lack of population-based studies and a clear definition of COVID-19, PASC prevalence estimates fluctuate considerably, said the researchers.
After adjusting the models, U-M said the researchers also found that:
- There were no statistically significant differences in 30-day or 60-day COVID-19 by race/ethnicity.
- Annual household income was a strong and significant predictor of 30-day COVID-19. Even after adjusting for demographic and clinical factors, respondents with an income less than $75,000 had about 40% higher prevalence of 30-day COVID-19 than respondents with an income at or above $75,000.
- Income was not significantly associated with 60-day COVID-19 in fully adjusted models.
- Respondents with a psychological condition had 42% higher prevalence of 60-day COVID-19.
- Self-reported acute illness severity was strongly associated with both 30-day and 60-day COVID-19.
“These results add to the growing body of evidence that a sizable proportion of symptomatic COVID-19 cases of varying severity experience PASC,” Fleischer said in a statement. “People are continuing to suffer from symptoms well after their initial illness, and the medical and public health communities need to help address this ongoing crisis.”
The Michigan COVID-19 Recovery Surveillance study will be examining a larger group of respondents with PASC who experienced COVID onset through September 2020.
The study was supported by the Michigan Public Health Institute, Michigan Department of Health and Human Services, U-M Rogel Cancer Center and the Department of Epidemiology at the U-M School of Public Health and the U-M Institute for Data Science.