• National-level survey data has been collected from children aged 0-14 in Denmark as part of the largest study to date into long COVID in children.
  • The study investigated the duration of long COVID symptoms alongside quality of life scores, confirming that children with a positive COVID test are more likely to have at least one symptom lasting more than two months after infection, than children who had never been diagnosed with COVID -19.
  • In older age groups (12 to 14 years), quality of life scores were higher and reports of anxiety were lower for children who had tested positive for COVID-19 than children who did not. didn’t, likely related to pandemic awareness and societal restrictions.
  • The authors say that knowledge of the burden of long COVID in children is essential to guide clinical recognition, care strategies and societal decisions such as lockdowns and vaccination. They recommend further research to better understand the long-term consequences of the COVID-19 pandemic on all children.

The largest study to date on long COVID symptoms in children aged 0-14 confirms that children who have been diagnosed with COVID-19 may have long COVID symptoms lasting at least two months. The study, published in The Lancet Child and adolescent healthused nationwide child sampling in Denmark and matched COVID-19 positive cases with a control group of children with no history of COVID-19 infection.

“The overall objective of our study was to determine the prevalence of long-lasting symptoms in children and infants, as well as quality of life and absence from school or daycare. Our results reveal that although that children with a positive diagnosis of COVID-19 are more likely to have lasting symptoms than children without a previous diagnosis of COVID-19, the pandemic has affected all aspects of the lives of all young people. the long-term consequences of the pandemic on all children will be significant in the future,” says Professor Selina Kikkenborg Berg, University Hospital Copenhagen, Denmark. [1].

Most previous studies on long COVID in young people have focused on teenagers [2], infants and toddlers being rarely depicted. In this research, surveys were sent to the mother or guardian of children aged 0-14 who had tested positive for COVID-19 between January 2020 and July 2021. In total, responses were received for almost of 11,000 children with a positive COVID-19. test result that were age- and sex-matched to more than 33,000 children who had never tested positive for COVID-19 [3].

The surveys asked participants about the 23 most common symptoms of Long COVID in children (identified by the January 2021 Long COVID Kids Rapid Survey [4]) and used the World Health Organization‘s definition of long COVID as symptoms for more than two months. The most commonly reported symptoms in children 0-3 years old were mood swings, skin rashes, and upset stomach. Among 4 to 11 year olds, the most commonly reported symptoms were mood swings, trouble remembering or concentrating, and skin rash, and among 12 to 14 year olds, fatigue, mood swings and memory or concentration problems.

The study results revealed that children diagnosed with COVID-19 across all age groups were more likely to have at least one symptom for two or more months than the control group. In the 0-3 year age group, 40% of children diagnosed with COVID-19 (478 of 1,194 children) had symptoms for more than two months, compared to 27% of controls (1,049 of 3,855 children). For the age group 4-11 years, the ratio was 38% of cases (1,912 out of 5,023 children) against 34% of controls (6,189 out of 18,372 children), and for the age group 12- By age 14, 46% of cases (1,313 of 2,857 children) versus 41% of controls (4,454 of 10,789 children) had long-lasting symptoms.

The nonspecific types of symptoms associated with long COVID are often experienced by otherwise healthy children; headaches, mood swings, abdominal pain, and fatigue are all symptoms of common ailments children experience that are unrelated to COVID-19. However, this study found that children with a positive diagnosis of COVID-19 were more likely to have long-lasting symptoms than children who had never had a positive diagnosis, suggesting that these symptoms were a presentation of a long COVID. This is supported by around a third of children who test positive for COVID-19 and who have symptoms that were not present before SARS-CoV-2 infection. Moreover, as the duration of symptoms increased, the proportion of children with these symptoms tended to decrease.

Generally, children diagnosed with COVID-19 reported fewer psychological and social problems than children in the control group. In older age groups, cases often felt less frightened, had less trouble sleeping, and felt less worried about what was about to happen to them. A likely explanation for this is increased awareness of the pandemic in older age groups, children in the control group being afraid of the unknown disease, and more restricted daily life due to their protection against the virus.

“The opportunity to undertake such research is rapidly closing as the vast majority of children have now had COVID-19 infection, for example 58% of children in Denmark have had laboratory confirmed infection between December 2021 and February 2022. Knowledge of long-term symptom burden in SARS-CoV-2 positive children is essential to guide clinical recognition, parental care, and societal decisions regarding isolation, confinement, non-pharmaceutical interventions, and vaccine strategies,” says Professor Selina Kikkenborg Berg. [1]

“Our findings align with previous studies of long COVID in adolescents showing that although the odds of children experiencing long COVID are low, especially compared to control groups, it should be recognized and treated seriously. More research will be beneficial to address and better understand these symptoms and the long-term consequences of the pandemic on children in the future. [1]

The authors acknowledge some limitations to the study, including a long recall period between diagnosis and taking the survey. The research relied on parent-reported data which is less accurate for psychological symptoms. It can also lead to selection bias, as mothers and guardians of children with more severe symptoms are often more likely to respond, leading to results representing the most affected children. Additionally, public testing for COVID-19 was not available until August 2020, meaning some children in the control group may have had undetected asymptomatic infections.

Writing in a linked comment, Maren Rytter, University of Copenhagen, Denmark, who was not involved in the study, said: “[Although] the study found that symptoms of any kind were slightly more common in children who had been infected with SARS-CoV-2…the overall impact on children of having had COVID-19 is likely small, and probably far less than the indirect effects of the pandemic. For most children with non-specific symptoms as a result of COVID-19, the symptoms are more likely to be caused by something other than COVID-19 and if related to COVID-19 they are likely to pass with time.


This study was funded by AP Møller and Chastine Mc-Kinney Møller Foundation. It was conducted by researchers from the University of Copenhagen, Denmark, and the University of Southern Denmark.

[1] Direct quote from the author and not found in the text of the article.
[3] Danish database with COVID-19 data, covering all Danes with a positive COVID-19 test:
[4] Survey of Long Covid symptoms in children:

The labels were added to this news release as part of a project led by the Academy of Medical Sciences to improve evidence reporting. For more information, please see: if you have any questions or comments , please contact The Lancet Press Office [email protected]


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