Long COVID in Icelandic Children: A Matched Cohort Study of Nonspecific Symptoms Following SARS-CoV-2 Infection

Purpose:Pediatric severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infections are usually mild and the mortality rates are low, but concerns have been raised about long-term symptoms that may resemble other postinfectious syndromes. Studies with robust control groups and high response rates have been few.Methods:We obtained identifiers for all 837 Icelandic children diagnosed with SARS-CoV-2 by PCR between March 2020 and June 2021 and contacted them by telephone. We asked about 10 physical and mental symptoms being present at least twice weekly for at least 2 months. Participants who reported symptoms were contacted again a year later. For each subject who completed the questionnaire, an age- and sex-matched comparator without SARS-CoV-2 infection was asked to complete the same questionnaire, and the risk difference was calculated.Results:Responses from 643 cases and 602 comparators were analyzed. Children who had been infected with SARS-CoV-2 were more likely to report one or more symptoms, except for anxiety/depression and sleep disturbances. Fatigue and loss of concentration were evidently more common in cases among teenagers (risk difference: 15%; 95% CI: 7-22% and 15%; 95% CI: 7-23%, respectively). At the second follow-up, close to a third of Long COVID cases had resolved but some participants had developed new persistent symptoms.Conclusion:Symptoms of Long COVID in children are common and impact their quality of life. The importance of further unraveling the pathophysiology of acute and long-term symptoms following SARS-CoV-2 infection in children is vital as well as potential preventive measures.