Tens of millions of children around the world have been infected with COVID-19, but we are just beginning to understand the long-term complications and impacts infection has on children and adolescents. We know that both adults and children can develop "Long COVID" symptoms, however there is significantly less data on children.
What studies have shown thus-far is that children and adolescents are as likely as adults to develop long COVID symptoms, and that many of these children continue to have persistent symptoms beyond one year post-infection. The long COVID symptoms in pediatric COVID-19 patients generally covered multiple systems, including respiratory, neurological, and cardiovascular systems, and so on.
Similar to adults with long COVID, the most commonly reported persistent or new-onset symptoms post-COVID infection were: dyspnea (difficulty breathing), fatigue, headache, shortness of breath, abdominal pain, difficulty concentrating, and muscle pain.
However, unlike adults, children and adolescents are more likely to experience post-COVID associated myocarditis, splenomegaly, appendicitis, though the overall risk of such severe complications were still very rare.
Other long COVID symptoms that were identified were developmental regressions, memory impairments, and other physical and psychological impairments that could have long-term impacts on these children.
Based on a systematic review and meta-analysis published in March 2023 of 40 studies with over 12,000 individuals, the pooled prevalence of any long COVID was 23.36 %. Nearly one quarter of pediatric COVID-19 survivors suffered from multi-system long COVID symptoms, even at 1 year post-infection. This is consistent with a June 2022 systematic review and meta-analysis of 21 studies including over 80,000 children and adolescents that found that the prevalence of long COVID was 25.24%.
An Italian prospective cohort study published in April 2023 (ahead of print), found that hospitalization for acute COVID-19 infection, preexisting comorbidities*, older (over age 10), and infection with the pre-Omicron variants were risk factors for developing long COVID conditions. Being asymptomatic during the acute infectious phase was found to be protective against long COVID symptoms.
The study concluded that while most children recovered over time, approximately one-in-twenty (5%) of those with long COVID at three months continued to report persistent symptoms at 18 months post-infection. The study did find that children with Omicron had shorter recovery periods than children infected with earlier variants. The study also did not find any protective factors associated with vaccination, however during the timeframe of the study (02/01/2020 to 10/31/2022), only 20% of the participants had been vaccinated. The participants were also heavily school-aged children, with a range from 4 - 11 years of age.
*Most common comorbidities in the study population were: allergies, cardiac, endocrine, gastrointestinal, genetic, hematological, and neurological diseases.
A January 2024 retrospective cohort study published in the journal Pediatrics found vaccination against COVID-19 provides a moderate protective effect against developing Long COVID. The effect increased with age, and wanes over time since vaccination.