New findings show long-COVID affects a significant proportion of children and teens, with symptoms lingering for years and demanding better care strategies.

Study: A 24-month National Cohort Study examining long-term effects of COVID-19 in children and young people. Image Credit: Lightspring / Shutterstock

A study published in the journal Communications Medicine reports the prevalence and consequences of post-coronavirus disease 2019 (COVID-19) symptoms in children and young individuals up to 24 months post-infection.

Background

A significant proportion of COVID-19 patients consistently experience a range of health complications even after months or years of the initial infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This condition is medically termed as long-COVID.

The Long COVID in Children and Young People (CLoCk) study has been designed to explore long-COVID symptoms in children and adolescents aged under 18 years. The study has reported findings on long-COVID in 20,202 children and adolescents living in England up to 12 months after their initial SARS-CoV-2 infection.

In the current study, scientists have analyzed the CLoCk study data to report long-COVID symptoms and their consequences in children and adolescents for up to 24 months post-SARS-CoV-2 infection. This extended follow-up is crucial for understanding the persistence of symptoms over time and their potential impact on quality of life.

Study Design

The study included a total of 12,632 children and adolescents from the CLoCk study who were 11 to 17 years old at the time of their initial SARS-CoV-2 testing (between September 2020 and March 2021).

The participants were categorized into four groups according to their infection status over the period of 24 months. The first group included participants who never tested positive for SARS-CoV-2. The second group included those who were initially test-negative but subsequently tested positive. The third group included those who were initially test-positive but did not have reinfection later on. The fourth group included those who were initially test-positive and also developed reinfection later on.

Participants reported long-COVID symptoms and their consequences, which were examined at 3, 6, 12, and 24 months after the initial SARS-CoV-2 infection. To operationalize long-COVID in children, the study used the Delphi research definition, focusing on persistent symptoms and associated difficulties in daily functioning.

Important Observations

All study participants reported experiencing some symptoms 24 months after their initial infection. The most frequently reported symptoms were tiredness, trouble sleeping, shortness of breath, and headaches.

A variation in symptom prevalence was observed between the study groups. While participants who never tested positive exhibited the lowest prevalence of symptoms, the highest prevalence was observed among participants who initially tested positive and later developed reinfection.

The study groups also observed a variation in the total number of reported symptoms. While 35% of participants who initially tested positive and subsequently developed reinfection reported no symptoms, 46% of participants who never tested positive for SARS-CoV-2 reported the same experience. However, even among the never-positive group, 14% experienced five or more symptoms, highlighting the non-specific nature of many symptoms reported.

Among participants who reported experiencing more than five symptoms, about 14% were from the never-positive group, and 21% were from the initial test-positive and subsequent reinfection group.

Despite significant variation in symptoms, only a slight variation in self-rated health, symptom severity, and symptom impact was observed between the study groups at a 24-month timepoint. This finding raises questions about whether self-perceived health metrics can fully capture the burden of long-COVID in children.

Considering the demographic characteristics of participants, the study found that long-COVID is more common among older participants, female participants, as well as socioeconomically deprived participants.

Participants who fulfilled the long-COVID Delphi research definition exhibited more difficulties, worse quality of life, and more tiredness than those who did not meet the long-COVID Delphi research definition.

Only 7.2% of the participants fulfilled the long-COVID Delphi research definition at 3-, 6-, 12-, and 24-month time points. These participants reported an average of five symptoms at 3 months, five at 6 months, six at 12 months, and five at 24 months post-infection. This consistent subgroup reflects a more severe and persistent burden of symptoms, emphasizing the need for targeted support.

Considering vaccination status, the study found no apparent trend in the number of reported symptoms, health status, quality of life, and symptom impact or severity between vaccinated and unvaccinated participants at 24 months.

Study Significance

The study finds that a considerable proportion of children and adolescents (aged 11 to 17) consistently experience, on average, five symptoms over the period of 24 months post-SARS-CoV-2 infection, irrespective of their infection status during this period.

While the most commonly reported symptoms are tiredness, trouble sleeping, shortness of breath, and headaches, the participants less frequently report abdominal pain, concentration difficulties, and muscle pain. Although reported by a minority, these less frequent symptoms can still significantly affect daily activities and warrant further attention.

The study used the long-COVID Delphi research definition to analyze symptoms, which, in contrast to the World Health Organization (WHO) definition, does not require symptoms to have arisen within the first three months of infection. It is the only definition currently being used for children and adolescents and is considered to be more powerful in capturing long-COVID symptoms, particularly for those who remained asymptomatic or unaware of having an infection during the acute SARS-CoV-2 infection phase.

Crucially, the study emphasizes that many of the reported symptoms are common in adolescents irrespective of their SARS-CoV-2 infection status, suggesting a potential overlap between long-COVID and general adolescent health issues.

Notably, the study could not find any significant variation in self-rated health, symptom severity, or symptom impact among children and adolescents with varying infection and vaccination status. Furthermore, the symptoms reported by participants are non-specific and often commonly reported in adolescents, even before the COVID-19 pandemic.

Considering the findings, scientists highlight the need for further studies to understand the pathophysiology, develop diagnostic tests, and identify effective interventions for long-COVID management in children and adolescents. In particular, longitudinal studies are essential to clarify the natural history of symptoms and their impact over time.