- A recent review included 14 international studies on long COVID in children and adolescents involving nearly 20,000 participants.
- Some studies indicated no difference in the symptoms reported by those who had experienced COVID-19 and those who had not.
- The review found little evidence to suggest that symptoms of long COVID typically last longer than 12 weeks in children and adolescents.
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Yet, some individuals experience ongoing health problems, such as fatigue, cardiorespiratory, and neurological symptoms, weeks after the initial onset of their illness — a phenomenon commonly referred to as long COVID.
While the CDC reports that post-COVID symptoms appear to be less common in children and adolescents than in adults, children have reported experiencing long-term health issues following a SARS-CoV-2 infection.
The review encompassed 14 studies involving 19,426 children and adolescents.
In these participants, for those who reported experiencing persistent symptoms after developing COVID-19, the most common symptoms reported 4–12 weeks after acute infection were headache, fatigue, sleep disturbance, concentration difficulties, and abdominal pain.
From the start of the pandemic to the beginning of September this year, nearly 5.3 million children have tested positive for SARS-CoV-2 in the United States, according to the American Academy of Pediatrics (AAP).
The new review authors point out that even if only a small number of those individuals experience long COVID, the overall impact can be considerable.
However, they found that almost all the existing studies had significant limitations, prompting the authors to stress in the review that new studies are urgently needed to look at the risk of long COVID in this population.
Review co-author Dr. Petra Zimmermann, a senior lecturer at the University of Fribourg in Switzerland and an honorary fellow at MCRI, spoke with Medical News Today.
She explained that health researchers need to have a clear understanding of the impact of long COVID in children and adolescents to help guide authorities in making vaccine policy decisions.
“As children are often asymptomatic or have mild symptoms when [contracting infection] with SARS-CoV-2, one of the reasons to [vaccinate] them is to protect them against long-term consequences from SARS-CoV-2, such as [multisystem inflammatory syndrome in children] and long COVID,” Dr. Zimmermann wrote.
“Therefore, we need to accurately determine the risk of long COVID in this age group. Often, just a single study is cited to give a prevalence of persisting symptoms. We wanted to summarize them to get a better overview.”
In the review, Dr. Zimmermann and co-authors Dr. Laure Pittet and Dr. Nigel Curtis found that some studies indicate no difference in the symptoms reported by those who had developed COVID-19 and those who had not.
According to the authors, this highlights how long COVID symptoms are difficult to distinguish from pandemic-associated symptoms.
“Only a few studies have a control group of children and adolescents who have not [acquired the infection],” Dr. Zimmermann pointed out to MNT.
“Of the five studies that did have a control group, two did not find a difference between the children who had [contracted the infection] and those who had not. This means that the symptoms attributed to long COVID are very difficult to differentiate from symptoms that [arise for other reasons related to the pandemic] — such as school closures, lockdowns, not being able to see friends or do sports and hobbies, seeing friends and family suffering or even dying from COVID-19, being worried to transmit the virus to others, and many more.”
Another significant finding of the review: the studies indicated symptoms of long COVID rarely last longer than 12 weeks in children and adolescents.
The review authors highlight several major limitations of the studies. They state that one problem is that no clear definition of long COVID currently exists, nor do researchers agree on how long the phenomenon typically lasts.
The review points out that over 200 symptoms have links to long COVID — many of which are also prevalent in the general population, including fatigue and joint paint.
“It is a new virus, so it is more difficult to study than something clinicians and researchers are familiar with,” Dr. Zimmermann told MNT. “Each day, we learn new things and have to adapt our clinical management and our research.”
Additionally, the review authors explain some of the studies relied on participants self-reporting that they had tested positive for SARS-CoV-2 rather than utilizing laboratory confirmation. Most studies also relied on self-reported symptoms without physical exams.
Another limitation that Dr. Zimmermann highlighted is that many of the studies had a low response rate. In the 2021
“It is likely that individuals with persisting symptoms are more likely to respond than those who feel healthy, which can lead to selection bias and overestimating the rate of persistent symptoms,” Dr. Zimmermann said.
Other studies, she added, recruited participants from support groups for parents of children experiencing long COVID. “This will also lead to an overestimation of the prevalence,” Dr. Zimmermann wrote.
Additionally, the studies included participants from a wide range of ages. The review’s authors suspect the prevalence and symptoms of long COVID vary between younger children and adolescents.
The researchers also point out that all of the studies took place before the Delta variant became prevalent. Children and adolescents who contract this variant may face a different risk of experiencing long COVID, they write — another factor that researchers should consider in future studies.
MNT also spoke with Dr. Tina Tan, a professor of pediatrics at Northwestern University’s Feinberg School of Medicine and pediatric infectious diseases attending at the Ann & Robert H. Lurie Children’s Hospital, both in Chicago.
She said the review does a good job of illustrating the urgent need for additional research on how long COVID impacts children and adolescents.
“This study is very good in pointing out the fact that we just need more specific and accurate information to determine: one, what the symptoms are, even though the symptoms probably in most kids are going to be very similar to what we see in adults, and then, two, what the consequences of children having these symptoms for prolonged periods of time might be,” Dr. Tan commented.
Earlier in the pandemic, Dr. Tan explained the general consensus was that children were less likely to develop COVID-19 and were more likely to be asymptomatic when they did develop it.
With the Delta variant, she added, more children are testing positive for SARS-CoV-2, and more are being hospitalized. Dr. Tan explained that she believes this will lead to more research into the impact of long COVID in children and adolescents.
“I think what’s also really important about this study is that it shows that kids do get COVID-19, and they do get sick with COVID-19. They can have long COVID symptoms, and this is one of the major reasons why kids who are eligible for vaccinations should be vaccinated.”
– Dr. Tan
The review authors recommend that future studies investigate the severity of the individual’s initial disease and consider how that impacts the likelihood of developing long COVID.
They also hope to see studies that include “rigorous control groups,” which would include children admitted to the hospital for reasons other than COVID-19.
“Also, the underlying mechanisms should be identified and whether long COVID can be prevented by vaccination,” Dr. Zimmermann told MNT.