Long COVID symptoms in SARS-CoV-2-positive children  aged 0–14 years and matched controls in Denmark  (LongCOVIDKidsDK): a national, cross-sectional study

Long COVID symptoms in SARS-CoV-2-positive children  aged 0–14 years and matched controls in Denmark  (LongCOVIDKidsDK): a national, cross-sectional study

Tiempo de lectura: 3 minutos

Lancet Child Adolesc Health

2022; 6: 614–23

Published Online

June 22, 2022

https://doi.org/10.1016/  S2352-4642(22)00154-7

See Comment page 595

Department of Cardiology

(Prof S Kikkenborg Berg PhD,

P Palm PhD,  Prof H Bundgaard DMSc,

A Vinggaard Christensen PhD),  Department of Paediatrics and  Adolescents Medicine

(U Nygaard PhD), and  Department of Infectious

Disease  (Prof S Dam Nielsen DMSc),  Rigshospitalet, Copenhagen  University Hospital,  Copenhagen, Denmark; Faculty  of Health and Medical Sciences,  University of Copenhagen,

Copenhagen, Denmark

(Prof S Kikkenborg Berg,  U Nygaard, Prof H Bundgaard,  Prof S Dam Nielsen); The  National Institute of Public  Health, University of Southern  Denmark, Copenhagen,  Denmark (M N S Petersen MSc,

S Rosenkilde MSc,  A B Thorsted MSc,  Prof A K Ersbøll PhD,

Prof L C Thygesen PhD)

Correspondence to:  Prof Selina Kikkenborg Berg,  Department of Cardiology,  Rigshospitalet, Copenhagen  University Hospital,

2100 Copenhagen, Denmark


Selina Kikkenborg Berg, Pernille Palm, Ulrikka Nygaard, Henning Bundgaard, Maria Nivi Schmidt Petersen, Siri Rosenkilde, Anne Bonde Thorsted,  Annette Kjær Ersbøll, Lau Casper Thygesen, Susanne Dam Nielsen, Anne Vinggaard Christensen.


Background After the acute phase of SARS-CoV-2 infection, children can develop long COVID symptoms. We aimed  to investigate the prevalence of long-lasting symptoms, the duration and intensity of symptoms, quality of life,  number of sick days and absences from daycare or school, and psychological and social outcomes in children aged  0–14 years who had been infected with SARS-CoV-2 relative to controls with no history of SARS-CoV-2infection.

Methods A nationwide cross-sectional study was conducted including children with a confirmed SARS-CoV-2-positive  PCR test (cases) and matched controls from Danish national registers. A survey was sent to mothers (proxy reporting)  of children aged 0–14 years who had had a positive SARS-CoV-2 test between Jan 1, 2020, and July  12, 2021, and a  control group matched (1:4) by age and sex. The survey included the Pediatric Quality of Life Inventory (PedsQL) and  the Children’s Somatic Symptoms Inventory-24 (CSSI-24) to capture current overall health and wellbeing, and ancillary  questions about the 23 most common long COVID symptoms. Descriptive statistics and logistic regression analysis  were used. Clinically relevant differences were defined as those with a Hedges’ score greater than 0·2. This study is  registered at ClinicalTrials.gov (NCT04786353).

Findings Responses to the survey were received from 10 997 (28·8%) of 38 152 cases and 33 016 (22·4%) of 147 212 controls  between July 20, 2021, and Sept 15, 2021. Median age was 10·2 years (IQR 6·6–12·8) in cases and 10·6 years (6·9–12·9) in  controls. 5267 (48·2%) cases and 15 777 (48·3%) controls were female, and 5658 (51·8%) cases and 16 870 (51·7%) controls  were male. Cases had higher odds of reporting at least one symptom lasting more  than 2 months than did controls in  the 0–3 years age group (478 [40·0%] of 1194 vs 1049 [27·2%] of 3855; OR 1·78 [95% CI 1·55–2·04], p<0·0001), 4–11 years  age group (1912 [38·1%] of 5023 vs 6189 [33·7%] of 18 372; 1·23 [1·15–1·31], p<0·0001), and 12–14 years age group  (1313 [46·0%] of 2857 vs 4454 [41·3%] of 10 789; 1·21 [1·11–1·32], p<0·0001). Differences in CSSI-24 symptom scores  between cases and controls were statistically significant but not clinically relevant. Small clinically relevant differences in  PedsQL quality-of-life scores related to emotional functioning were found in favour of cases in the children aged  4–11 years (median score 80·0 [IQR 65·0–95·0]) in cases vs 75·0 [60·0–85·0] in controls; p<0·0001)  and 12–14 years  (90·0 [70·0–100·0] vs (85·0 [65·0–95·0], p<0·0001). PedsQL social functioning scores were also higher in cases  (100·0 [90·0–100·0] than controls (95·0 [80·0–100·0]) in the 12–14 years age group (p<0·0001; Hedges g>0·2).

Interpretation Compared with controls, children aged 0–14 years who had a SARS-CoV-2 infection had more prevalent  long-lasting symptoms. There was a tendency towards better quality-of-life scores related to emotional and social  functioning in cases than in controls in older children. The burden of symptoms among children in the control group  requires attention. Long COVID must be recognised and multi-disciplinary long COVID clinics for children might be  beneficial.

Funding A P Møller and Chastine Mc-Kinney Møller Foundation.

Copyright © 2022 Elsevier Ltd. All rights reserved.


Children worldwide are at risk of SARS-CoV-2 infection1  because of a lack of approved vaccines for children aged  0–4 years, few countries recommending vaccination for  children aged 5–11 years, low vaccine uptake  among  children overall, difficulties practising physical distancing  and,  in  particular,  low  vaccine  effectiveness  against the

omicron variant of SARS-CoV-2.2 Thus, a considerable  number of children have been infected with SARS-CoV-2,3  including in Denmark,  where  58%  of all  children   have

had laboratory-confirmed  infection during the period  from Dec 15, 2021, to Feb 15, 2022.4 This situation leaves a  considerable number of children at risk of long-term  sequelae following SARS-CoV-2 infection (generally  referred to as long COVID, post-COVID-19 condition, or  post-COVID-19 syndrome). Different definitions of this  condition exist, but WHO has defined post-COVID-19  condition among adults as persistent or fluctuating symp-  toms with an influence on daily functioning following  SARS-CoV-2 infection for at least 2 months that cannot be

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