Long COVID persists in children

New evidence shows that a significant proportion of children and adolescents are affected by Long COVID, with symptoms lasting for years and requiring better care strategies.

Study: A 24-month national cohort study examining the long-term effects of COVID-19 in children and adolescents. Image credit: Lightspring / Shutterstock

A study published in the journal Communication medicine reports the prevalence and consequences of symptoms of post-coronavirus disease 2019 (COVID-19) in children and adolescents up to 24 months after infection.

background

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

The Long COVID in Children and Young People (CLoCk) study was designed to examine long COVID symptoms in children and adolescents under 18 years of age. The study reported results on long COVID in 20,202 children and young people living in England up to 12 months after their first SARS-CoV-2 infection.

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

Study design

A total of 12,632 children and adolescents from the CLoCk study who were 11 to 17 years old at the time of their first SARS-CoV-2 test (between September 2020 and March 2021) took part in the study.

Participants were divided into four groups according to their infection status over the 24-month period. The first group included participants who never tested positive for SARS-CoV-2. The second group included those who initially tested negative but subsequently tested positive. The third group included those who initially tested positive but were not later infected again. The fourth group included those who initially tested positive and later developed a new infection.

Participants reported long-term COVID symptoms and outcomes assessed at 3, 6, 12, and 24 months after the first SARS-CoV-2 infection. To operationalize long-COVID in children, the study used the Delphi research definition and focused 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 commonly reported symptoms were fatigue, difficulty sleeping, shortness of breath and headache.

Variation in symptom prevalence was observed between study groups. While participants who never tested positive had 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 variation in the total number of symptoms reported. 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 in the never-positive group, 14% experienced five or more symptoms, highlighting the nonspecific nature of many reported symptoms.

Of the participants who reported having more than five symptoms, about 14% were from the group that never tested positive and 21% were from the group who initially tested positive and subsequently reinfected.

Despite significant differences in symptoms, little variation in self-rated health status, symptom severity, and symptom impact was observed between study groups at 24 months. This finding raises the question of whether self-assessed health metrics can fully capture children’s exposure to long-term COVID.

Taking into account the demographic characteristics of the participants, the study found that long-COVID is more common in older participants, female participants and socioeconomically disadvantaged participants.

Participants who met the Long COVID Delphi research definition experienced more difficulties, poorer quality of life, and more fatigue than those who did not meet the Long COVID Delphi research definition.

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

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

Study Importance

The study finds that a significant proportion of children and adolescents (aged 11 to 17 years) experience an average of five symptoms over the 24 month period after SARS-CoV-2 infection, regardless of their infection status this period.

While the most commonly reported symptoms are fatigue, difficulty sleeping, shortness of breath and headaches, participants are less likely to report abdominal pain, difficulty concentrating and muscle pain. Although these rarer symptoms are reported by a minority, they can significantly impact daily activities and require further attention.

To analyze symptoms, the study used the Long COVID Delphi research definition, which, unlike the World Health Organization (WHO) definition, does not require symptoms to have occurred within the first three months of infection. It is the only definition currently used for children and adolescents and is considered more meaningful in detecting long-term COVID symptoms, particularly for those who remained asymptomatic or contracted infection during the acute SARS-CoV-2 infection phase were not aware.

Crucially, the study highlights that many of the reported symptoms are common in adolescents regardless of their SARS-CoV-2 infection status, suggesting a possible overlap between long-term COVID and general health problems in adolescents.

In particular, the study did not find any significant differences in self-assessment of health status, symptom severity or symptom impact among children and adolescents with different infection and vaccination statuses. Additionally, the symptoms reported by participants are non-specific and commonly reported in adolescents prior to the COVID-19 pandemic.

Given the results, scientists emphasize the need for further studies to understand the pathophysiology, develop diagnostic tests and identify effective interventions for long-term COVID treatment in children and adolescents. Longitudinal studies are particularly important to clarify the natural course of symptoms and their effects over time.