Reference: Ann Intern Med. 2021 Jul 6
Some diseases (such as SARS and AIDS) are first described in case series and cohort reports as syndromes, generally defined as heterogeneous clusters of symptoms or signs with an unknown cause. In July 2020, early reports indicated that COVID-19 was sometimes associated with prolonged symptoms, and subsequent research has confirmed a higher risk of death and significant morbidity persisting long after hospitalization for COVID. Even younger individuals without comorbidities have been reported to suffer long-term symptoms affecting the quality of life. At this point, the NIH hasn’t settled on a firm definition of what is most often called post-acute COVID-19 syndrome. This month, the Annals of Internal Medicine published another early report on the phenomenon sometimes described as “long haul COVID,” this time in patients who did not require hospitalization.
The CoviCare group in Switzerland looked at 410 symptomatic people diagnosed with COVID in the Spring of 2020 who did not require hospitalization. They were asked about symptoms online or telephonically at baseline, during the initial phase of their disease, at one month, and then 7-9 months after their initial diagnosis. About one-third were lost to follow-up. Baseline questions covered symptoms such as fever and rash, but follow-up questionnaires also asked about problems ranging from insomnia to hair loss and included overall functional assessments
About 40% of patients had persistent but usually mild and non-disabling symptoms at 7-9 months. The most common symptoms were fatigue and smell/taste disturbances, although dyspnea and neuropsychiatric dysfunction (memory loss, insomnia or concentration difficulties) each affected a small group of people (about 5% each). Rates of severe symptoms were low.
The information from this cohort is interesting, but we remain firmly in the hypothesis-generating stage. While the symptoms being described as long-haul syndrome may end up being a distinct phenomenon, they could also just be part of COVID recuperation. It’s also possible that the ubiquity of the ongoing pandemic and our collective societal stress is a confounder, as the people with COVID were not compared to non-infected controls. We don’t know if the one out of three initial respondents who didn’t participate in follow-up were similar or different from the responders. This study looked at people within a specific range of baseline illness severity, so we can’t generalize the findings to patients who were asymptomatic or hospitalized. The data is helpful, but significant uncertainty remains. We’ve been in the position of only having cohort and case series data before - at the beginning of this pandemic and other epidemics. Remember how frustrating it was 20 months ago when we only had cohort studies and case series describing some people from a wet market with severe acute respiratory syndrome? We are in for a long haul to understand the long-term effects of COVID.
For more information, see the topic COVID-19 (Novel Coronavirus) in DynaMed.
DynaMed EBM Focus Editorial Team
This EBM Focus was written by Dan Randall, MD, Deputy Editor at DynaMed. Edited by, Alan Ehrlich, MD, Executive Editor at DynaMed and Associate Professor in Family Medicine at the University of Massachusetts Medical School; Carina Brown, MD, Assistant Professor at Cone Health Family Medicine Residency; Katharine DeGeorge, MD, MS, Associate Professor of Family Medicine at the University of Virginia and Clinical Editor at DynaMed; Nicole Jensen, MD, family physician at WholeHealth Medical; Tanya Tupper, RT(N), CNMT, PET, Senior Medical Writer at DynaMed, Vincent Lemaitre, PhD, Medical Writer at DynaMed and Christine Fessenden, Editorial Operations Assistant at DynaMed.