A Third of COVID-19 Patients Report Persistent Symptoms 6 Months After Illness

February 28, 2021
Jonna Lorenz

Symptoms of COVID-19 can persist for months in about a third of cases, including among those with mild illness, a new study confirms.

About a third of patients with coronavirus disease 2019 (COVID-19) reported persistent symptoms in a survey completed an average of 6 months after the onset of their illness, a small study from the University of Washington found.

The longitudinal prospective cohort study, published in JAMA Network Open, included 177 people who completed follow-up questionnaires between 31 and 300 days after illness onset at an average of 169 days.

“The primary take home message is that even in relatively young, healthy individuals, and even in those who have a mild case of COVID-19, symptoms can last for months after infection and can adversely impact quality of life,” co-author Denise J. McCulloch, MD, MPH, infectious disease fellow at the University of Washington, told Contagion®.

Most of those surveyed—150 (84.7%)—were outpatients who reported mild symptoms, 11 (6.2%) were asymptomatic and 16 (9%) were hospitalized with moderate or severe illness.

People age 65 and older were most likely to report persistent symptoms (43.3% of 30 patients), followed by those aged 40 to 64 (30.1% of the 83), and patients aged 18 to 39 (26.6% of the 64).

“I was surprised at how many people reported persistent symptoms 6 months after their infection,” McCulloch said. “Persistent symptoms have been more widely reported in cohorts of hospitalized patients, so we were surprised to see how often it occurred in this group of people who were fairly young and healthy, the vast majority of whom did not require hospitalization for their illness.”

Among those outpatients who originally reported mild symptoms, 49 (32.7%) reported at least 1 persistent symptom during the follow-up survey, compared with 5 (31.3%) of those hospitalized and 1 (4.8%) in the healthy control group. Among patients with hypertension or diabetes, 11 (35.5%) reported persistent symptoms.

“I would want clinicians to encourage COVID-19 vaccination for all of their patients when it is available to them, not just those who are considered high risk,” McCulloch said. “I believe our results underscore the importance of COVID vaccination even in young, healthy individuals, in order to help prevent COVID-19 infection and the potential for long-term symptoms.”

The most common persistent symptoms reported in the follow-up survey were fatigue and loss of taste or smell, both of which were reported among 24 patients (13.6%). Other symptoms included brain fog (2.3%). Health-related quality of life (HRQoL) was worse for 51 (30.7%) outpatients and hospitalized patients, and 14 patients (7.9%) reported negative impacts on at least 1 activity of daily living such as household chores.

“We plan to continue to survey the individuals in our study for 2 years to see whether their symptoms improve over time,” McCulloch said. “Also, many medical centers, including the University of Washington, are creating post-COVID clinics to help care for these patients following their illness. I hope that in partnership with these post-COVID clinics, researchers can work to understand what causes prolonged symptoms, and how these symptoms can be alleviated.”

The study is consistent with previous research, including a study by investigators at the University of Geneva that found that 33% of patients who were diagnosed with SARS-CoV-2 infection but did not require hospitalization still reported lingering symptoms 6 weeks after their diagnosis.

The long-term consequences of COVID-19 have been a growing concern during the pandemic.

On Feb. 23, the National Institutes of Health launched an initiative to study cases of COVID-19 in which symptoms persist long past the initial stages of the illness. Referred to informally as COVID-19 long haulers or long COVID, the NIH has termed these prolonged health consequences as Post-Acute Sequelae of SARS-CoV-2 infection (PASC).

The NIH PASC Initiative announced its first Research Opportunity Announcements (ROAs), which offer open funding for ongoing and new research studies that address PASC as part of $1.15 billion in funding over four years passed by Congress in December.

The Infectious Diseases Society of America (IDSA) recently held a news briefing addressing the increasing need for clinics focusing on the aftermath of COVID-19.