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Illness duration and symptom profile in symptomatic UK school-aged children tested for SARS-CoV-2

Our take —

This descriptive study characterized the symptom duration and burden of 1,734 symptomatic children with a positive SARS-CoV-2 test and matched controls in the UK between September 1, 2020 and January 24, 2021. Among this self-selected sample of children with symptomatic COVID-19, long-term symptoms reported by adult proxy via mobile phone app were relatively rare (4.4% at 28 days and 1.8% at 56 days). Children who tested negative for SARS-CoV-2 were less likely to have long-term symptoms (0.9% at 28 days) than those with COVID-19, though it is possible that the latter were more likely to perceive symptoms given media reports of long-term sequelae of COVID-19. Although the self-selected participation in this study might limit its generalizability, the findings add to a small but growing evidence base suggesting that long term persistence of COVID-19 symptoms among children is rare.

Study design

Prospective Cohort

Study population and setting

This prospective cohort study included children aged 5-17 years in the United Kingdom with COVID-19 symptoms, whose data was reported by an adult proxy to the mobile-phone based COVID-Symptom Study. This analysis included children who were symptomatic and completed SARS-CoV-2 testing (PCR or lateral flow antigen testing)  between September 1, 2020 (when school started in the UK) and January 24, 2021. Participation in the study was voluntary and all data was self-reported by adult proxy; after enrollment participants received daily prompts to report symptoms and SARS-CoV-2 testing and results throughout the study period. Illness duration was calculated from the first reported symptom until recovery or reporting ceased. Symptom burden was the number of different reported symptoms over the first week, first 28 days, and the entire illness duration. Children with positive SARS-CoV-2 tests were compared to children who reported symptoms but tested negative for SARS-CoV-2, matched 1:1 for age, gender, and week of testing. The study compared illness duration and symptom burden based on SARS-CoV-2 test positivity and among younger (5-11 years old) versus older (12-17 years old) children.

Summary of Main Findings

Of the 258,790 UK children aged 5-17 years with proxy-reported symptoms between March 24, 2020 and February 22,2021, 6,975 reported positive SARS-CoV-2 test results, 1,912 of whom met the criteria to calculate illness duration. The analytic sample, limited to children tested between September 1, 2020 and January 24, 2021, included 1,734 children, 588 aged 5-11 years and 1,146 aged 12-17 years. COVID-19 symptoms lasted a median of 6 days (interquartile range [IQR] 3,11 days) compared to a median 3 days (IQR 2, 7 days) of symptoms in matched SARS-CoV-2 negative controls. The older group had a slightly longer symptom duration than the younger children (median 7 days, IQR 3, 12 days versus median 5 days, IQR 2, 9 days). Overall, the most common reported symptoms among children with COVID-19 were headache (n=1,079, 62.2%) and fatigue (n=954, 55%). Younger children were more likely to report fever (n=257, 43.7%), sore throat (n=213, 36.2%), or abdominal pain (n=163, 27.7%), whereas older children were more likely to report sore throat (585, 51%), loss of smell (n=554, 48.3%), and fever (n=396, 34.6%). Overall, 77 children with COVID-19 (4.4%, 95% CI 3.5%, 5.5%) had proxy-reported symptoms that lasted 28 or more days (5.1% among older children and 3.1% among younger children), compared with 15 children in the symptomatic group that tested negative (0.9%). Among the children with COVID-19 symptoms lasting 28 days or more, fatigue (n=65, 84.%), headache (n=60, 77.9%), loss of smell (n=60, 77.9%), and sore throat (n=57, 74%) were the most common symptoms over the course of the disease. Fatigue was also the most common symptom among matched proxy-reported children who tested negative for SARS-CoV-2. Only 25 of the 1379 with follow-up time through 56 days had COVID-19 persistent symptoms by that time (1.8%, 95% CI 1.2%, 2.7%).These results did not change when they further excluded children (n=183, 10.5%) who tested positive and reported COVID-19 symptoms but did not have a reported asymptomatic day (e.g., reporting stopped and the authors assumed the child was asymptomatic for the primary analysis).

Study Strengths

This study measured COVID-19 symptom duration in children, a population for whom there is relatively little data on post-acute sequelae of COVID-19. Symptoms were reported prospectively, reducing recall bias. Children with similar symptoms who had tested negative for SARS-CoV-2 were matched to cases on key variables to serve as a control group.

Limitations

It is difficult to assess how representative children with proxy-reported symptoms in a mobile application are to other children in the United Kingdom or children who live elsewhere. It is likely that their proxy is more health conscious than the proxies of children who did not report symptoms, for both children with and without diagnosed SARS-CoV-2 infections. It is also unclear how accurate proxy-reported symptoms may be for potentially more subtle symptoms such as fatigue or headache, or how proxy-symptom reporting could vary based on a child’s age. Although the control group is very helpful in making a comparison, these factors make it difficult to assess how symptom misclassification may bias the symptom duration estimates, especially if symptom reporting changes after a SARS-CoV-2 diagnosis. If a SARS-CoV-2 diagnosis makes proxies more attuned to a child’s symptoms, for example, the difference in symptom duration may overestimate the difference between the duration of COVID-19 compared to infections with similar symptoms.

Value added

This study provides information about COVID-19 symptom duration in children aged 5-17 years and compares COVID-19 symptoms and their duration to other illnesses that cause similar symptoms.

This review was posted on: 18 October 2021