Study explores long COVID symptoms in kids under 14

A study of children aged 0–14 years has confirmed that children who have received a positive COVID-19 diagnosis can experience symptoms lasting at least two months.

“The overall aim of our study was to determine the prevalence of long-lasting symptoms in children and infants, alongside quality of life and absence from school or day care,” said Professor Selina Kikkenborg Berg, Copenhagen University Hospital, Denmark.

Researchers used national level sampling of children in Denmark and matched COVID-19 positive cases with a control group of children with no prior history of a COVID-19 infection.

“Our results reveal that, although children with a positive COVID-19 diagnosis are more likely to experience long-lasting symptoms than children with no previous COVID-19 diagnosis, the pandemic has affected every aspect of all young people’s lives. Further research into the long-term consequences of the pandemic on all children will be important going forwards,” Kikkenborg Berg said.

Most previous studies of long COVID in young people have focused on adolescents¹, with infants and toddlers seldom represented. In this research, surveys were sent to the mother or guardian of children between 0 and 14 years who had tested positive for COVID-19 between January 2020 and July 2021. In total, responses were received for almost 11,000 children with a positive COVID-19 test result who were matched by age and sex to over 33,000 children who had never tested positive for COVID-19².

As a part of the study, participants were asked about the 23 most common symptoms of long COVID in children (identified by the Long COVID Kids Rapid Survey January 2021³) and used the World Health Organization definition of long COVID as symptoms lasting more than two months. The most commonly reported symptoms among children 0–3 years old were mood swings, rashes and stomach aches. Among those 4–11 years old the most commonly reported symptoms were mood swings, trouble remembering or concentrating and rashes, and among those 12–14 years old, fatigue, mood swings and trouble remembering or concentrating.

The types of non-specific symptoms associated with long COVID are often experienced by otherwise healthy children; headache, mood swings, abdominal pain and fatigue are all symptoms of common ailments that children experience which are unrelated to COVID-19. However, this study revealed that children with a positive COVID-19 diagnosis were more likely to experience long-lasting symptoms than children who had never had a positive diagnosis, suggesting that these symptoms were a presentation of long COVID. This is supported by approximately one-third of children with positive COVID-19 tests experiencing symptoms that were not present before the SARS-CoV-2 infection. In addition, with increasing duration of symptoms, the proportion of children with those symptoms tended to decrease.

Generally, children diagnosed with COVID-19 reported less psychological and social problems than children in the control group. In older age groups, quality of life scores were higher, and reports of anxiety were lower for children who had tested positive for COVID-19 than children who had not, likely linked to awareness about the pandemic and societal restrictions.

“The opportunity to undertake such research is rapidly closing as the vast majority of children have now had a COVID-19 infection, for example 58% of children in Denmark had lab-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 caregiving and societal decisions about isolation, lockdown, non-pharmaceutical interventions and vaccine strategies,” Kikkenborg Berg said.

“Our findings align with previous studies of long COVID in adolescents showing that, although the chances of children experiencing long COVID is low, especially compared to control groups, it must be recognised and treated seriously. More research will be beneficial to treat and better understand these symptoms and the long-term consequences of the pandemic on children going forward.”

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 frequent in children who had been infected with SARS-CoV-2 … the overall impact on children of having had COVID-19 is probably small, and likely much less than the impact of the indirect effects of the pandemic. For most children with non-specific symptoms following COVID-19, the symptoms are more likely to be caused by something other than COVID-19 and if they are 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 https://www.thelancet.com/journals/lanchi/article/PIIS2352-4642(22)00004-9/fulltext
2 Danish database with COVID-19 data, covering all Danes with a positive COVID-19 test: https://miba.ssi.dk/forskningsbetjening/tilgaengelig-data
3 Child Long Covid Symptoms Survey: https://www.longcovidkids.org/long-covid-statistics?pgid=kkl2tuxu-fa53fc07-b96a-4584-bd85-4669b6dca6f2}

Image credit: ©stock.adobe.com/au/Raul Mellado