Among scientists, the existence of long COVID-19 in children and adolescents has been the subject of debate.
Published by a Mexican multidisciplinary group in Scientific Reports, the first study is a systematic review and meta-analysis. It identified mood symptoms as the most prevalent clinical manifestations of long COVID-19 in children and adolescents. These symptoms included sadness, tension, anger, depression, and anxiety (16.50%); fatigue (9.66%); and sleep disorders (8.42%).
The second study, LongCOVIDKidsDK, was conducted in Denmark. It compared 11,000 children younger than 14 years who had tested positive for COVID-19 with 33,000 children who had no history of COVID-19. The study was published in The Lancet Child and Adolescent Health.
Definitions are changing
In their meta-analysis, the researchers estimated the prevalence and counted signs and symptoms of long COVID-19, as defined by the United Kingdom’s National Institute for Health and Care Excellence. Long COVID-19 was defined as the presence of one or more symptoms more than 4 weeks after SARS-CoV-2 infection. For search terms, the researchers used “COVID-19,” “COVID,” “SARSCOV-2,” “coronavirus,” “long COVID,” “postCOVID,” “PASC,” “long-haulers,” “prolonged,” “post-acute,” “persistent,” “convalescent,” “sequelae,” and “postviral.”
Of the 8,373 citations returned by the search as of Feb. 10, 2022, 21 prospective studies, 2 of them on preprint servers, met the authors’ selection criteria. Those studies included a total of 80,071 children and adolescents younger than 18 years.
In the meta-analysis, the prevalence of long COVID-19 among children and adolescents was reported to be 25.24% (95% confidence interval, 18.17-33.02; I2, 99.61%), regardless of whether the case had been asymptomatic, mild, moderate, severe, or serious. For patients who had been hospitalized, the prevalence was 29.19% (95% CI, 17.83-41.98; I2, 80.84%).
These numbers, while striking, are not the focus of the study, according to first author Sandra Lopez-Leon, MD, PhD, associate professor of pharmacoepidemiology at Rutgers University, New Brunswick, N.J. “It’s important that we don’t focus on that 25%,” she said in an interview. “It’s a disease that we’re learning about, we’re at a time when the definitions are still changing, and, depending on when it is measured, a different number will be given. The message we want to give is that long COVID-19 exists, it’s happening in children and adolescents, and patients need this recognition. And also to show that it can affect the whole body.”
The study showed that the children and adolescents who presented with SARS-CoV-2 infection were at higher risk of subsequent long dyspnea, anosmia/ageusia, or fever, compared with control persons.
In total, in the studies that were included, more than 40 long-term clinical manifestations associated with COVID-19 in the pediatric population were identified.
The most common symptoms among children aged 0-3 years were mood swings, skin rashes, and stomachaches. In 4- to 11-year-olds, the most common symptoms were mood swings, trouble remembering or concentrating, and skin rashes. In 12- to 14-year-olds, they were fatigue, mood swings, and trouble remembering or concentrating. These data are based on parent responses.
The list of signs and symptoms also includes headache, respiratory symptoms, cognitive symptoms (such as decreased concentration, learning difficulties, confusion, and memory loss), loss of appetite, and smell disorder (hyposmia, anosmia, hyperosmia, parosmia, and phantom smell).
In the studies, the prevalence of the following symptoms was less than 5%: hyperhidrosis, chest pain, dizziness, cough, myalgia/arthralgia, changes in body weight, taste disorder, otalgia (tinnitus, ear pain, vertigo), ophthalmologic symptoms (conjunctivitis, dry eye, blurred vision, photophobia, pain), dermatologic symptoms (dry skin, itchy skin, rashes, hives, hair loss), urinary symptoms, abdominal pain, throat pain, chest tightness, variations in heart rate, palpitations, constipation, dysphonia, fever, diarrhea, vomiting/nausea, menstrual changes, neurological abnormalities, speech disorders, and dysphagia.
The authors made it clear that the frequency and severity of these symptoms can fluctuate from one patient to another.
“The meta-analysis is important because it brings together 21 studies selected from more than 8,000 articles – and in them, a large number of children – to study the most common manifestations of long COVID-19,” Gabriela Ensinck, MD, head of the infectious diseases department at the Víctor J. Vilela Children’s Hospital in Rosario, Argentina, told this news organization. Dr. Ensinck did not participate in the study. “The important thing here is that long COVID-19 exists in pediatrics. And that it is a prolongation of signs or symptoms over time, a time for which there is no single definition.”
“It’s a snapshot of all the symptoms that can remain after COVID-19,” Dr. Lopez-Leon explained. “The meta-analysis seeks to see if there’s an association between having had COVID-19 and having the symptoms, but at no time does it speak of causality.”
The prevalence of symptoms largely depends on the time since the onset of acute COVID-19. Most symptoms improve over time. In the studies that were included in the meta-analysis, the follow-up time varied between 1 and 13 months. It is important to understand what symptoms are associated with each period after the onset of infection, the authors said.