According to a new study, the four most common symptoms recorded 8 months after a mild case of COVID-19 are loss of smell, loss of taste, shortness of breath, and exhaustion.
One out of every ten people had at least one moderate-to-severe symptom that had a negative impact on their quality of life.
“Even if you are young and previously healthy, a mild COVID-19 infection may result in long-term consequences,” said senior author Charlotte Thålin, MD, from the department of clinical sciences at Danderyd Hospital of the Karolinska Institute in Stockholm, Sweden.
Thålin and colleagues studied the COVID-19-related interactions of over 1,000 Swedish healthcare employees over the course of a year and reported their findings in JAMA, the American Medical Association’s journal.
Long-haul travel has been linked to an increase in cognitive problems such as memory and attention, but the researchers found no evidence of this. COVID-19 is a human-infectious virus.
After asymptomatic COVID-19 cases, the researchers found no increased risk of long-term symptoms.
Previous research found severe long-term symptoms, including heart palpitations and neurologic impairments, among people hospitalized with COVID-19. The absence of these more severe symptoms after mild COVID-19 is “reassuring,” Thålin said.
Adding to Existing Evidence
This research “adds to the growing body of literature showing that people recovering from COVID have reported a diverse array of symptoms lasting for months after initial infection,” said Lekshmi Santhosh, MD, doctor faculty lead at the University of California, San Francisco Post-COVID OPTIMAL Clinic.
The current findings are part of an ongoing study looking at long-term immunity. Health care professionals enrolled in the research between April 15 and May 8, 2020, and have blood tests for coronavirus antibodies every 4 months. The researchers compared the symptoms of participants with mild cases of COVID-19 reported with those who never tested positive for coronavirus antibodies.
The results show that 26% of those who had COVID-19 previously had at least one moderate-to-severe symptom that lasted more than 2 months, compared with 9% in the control group. Of the people with mild COVID-19 cases, 11% reported at least one symptom that negatively affected work, social, or home life after 8 months, vs only 2% of the control group.
“These data mirror what we have seen across long-term cohorts of patients with COVID-19 infection. Notably, mild illness among previously healthy individuals may be associated with long-term persistent symptoms,” said Sarah Jolley, MD, a pulmonologist specializing in critical care at the UCHealth University of Colorado Hospital in Aurora and director of the Post-COVID Clinic.
“In this cohort, similar to others, this seems to be more pronounced in women,” Jolley added.
The study’s findings “tracks with a lot of the other work we’re seeing,” said David Putrino, Ph.D., director of rehabilitation innovation at Mount Sinai Health System in New York City, who works with patients with long COVID.
Interestingly, the number of people with persistent symptoms might be underestimated in this research, Putrino said. “Antibodies are not an entirely reliable biomarker. So what the researchers are using here is the most conservative measure of who may have had the virus.”
Furthermore, unlike many of the people with long-haul COVID-19 he treats— ones who are “really struggling” — the health care workers studied in Sweden are functioning well enough to perform their duties at the hospital, so the study group may not represent the general population.
“We’re really just starting to understand the long-term effects of COVID-19,” Putrino said. “This is something we’re going to see a lot of moving forward.”