Danish study of long COVID in teens

As an aftermath of the extended lockdowns and social distancing restrictions, Coronavirus disease 2019 (COVID-19) has impacted the quality of life of children and adolescents worldwide, not only physically due to the infection, but also mentally. A high level of anxiety and depression has been reported among pediatric patients and adolescents, many of whom were deprived of social interaction with peers during the pandemic.

Additionally, an array of physical symptoms also persisted after severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) infection, for instance – fatigue, headaches, and shortness of breath. These symptoms continued for several months after the infection and were collectively termed long COVID. Although the World Health Organization (WHO) has defined long COVID in adults, a definite spectrum of symptoms defining post-COVID manifestations has not yet been described in children and adolescents.

Study: Long COVID symptoms in SARS-CoV-2-positive adolescents and matched controls (LongCOVIDKidsDK): a national, cross-sectional study. Image Credit: Good Studio / Shutterstock.com

The study

A new study published in The Lancet: Child and Adolescent Health journal was based on the hypothesis that SARS-CoV-2 infection could impact the prevalence, intensity, and duration of long-lasting symptoms, psychological and social outcomes, school absence due to illness.

This cross-sectional study investigated the health outcomes and symptoms of long COVID  in adolescents who tested positive for SARS-CoV-2. This study compared SARS-CoV-2 positive individuals (case group) to a control group that had never been infected with SARS-CoV-2.

Symptoms that lasted for more than two months were explored for – the duration, intensity, and overall quality of life of the adolescents.

Additionally, social and psychological outcomes were compared between the two groups. Patients were also evaluated for new symptoms that developed after a positive test report—which had not been reported before testing.

The LongCOVIDKidsDK study was a national study conducted among adolescents of Denmark. Overall, 121,572 adolescents were invited to participate in this study, of which 24,315 were included the case group and 97,257 formed the control group. Participants were asked to complete The Children’s Somatic Symptoms Inventory-24 (CSSI-24) questionnaire, The Pediatric Quality of Life (PedsQL) questionnaire, and a survey providing information on a list of the 23 most common long COVID symptoms which were identified in 2021 (Long COVID Kids Rapid Survey January 2021).

Findings

A total of 6,630 patients (case group) responded; 2,997 patients belonged to the long COVID group. Only 21,640 participants responded and were eligible to constitute the control group.

It was found that in the case group, 61.9% of the participants experienced at least one symptom for more than two months compared to 57% in the control group. Interestingly, more female participants had the symptoms for more than two months compared to males in both groups. It was also reported that four weeks after infection, 65.7% of the participants from the case group experienced at least one new symptom that was not present before testing positive for SARS-CoV-2 infection. A higher number of participants from  the case group reported 16 or more days of sickness or absence from school than the control group

Significantly lower symptoms scores on the CSSI-24 questionnaire (two-week recall) and substantially better quality of life (physical, emotional, social and school functioning) on the PedsQL questionnaire (four-week recall) were deduced in the case group. In addition, lesser participants from the case group seemed to be worried, suffered sleep disturbances or experienced stigma from peers and were teased than the control group. These experiences were the psychological and social outcomes in the PedsQL questionnaire.

The most-reported long COVID symptoms were fatigue, loss of appetite, headache, shortness of breath,  lack of attention and memory loss. Participants in the case group had better quality of life scores on the PedsQL than in the control group. Long COVID symptoms in the case group had a mean of 1.3 not known before the positive SARS-CoV-2 test and presented eight weeks after the positive test.

Participants in the case group had a significantly lower symptom score. This group had a better quality of life than the control group concerning physical and emotional functioning. Furthermore, participants in the case group had more sick days – and 16 more days of school absence on average.

The mean long COVID symptoms in the case group with severe acute symptoms was 3.3. Those who reported mild acute symptoms had mean long COVID symptoms of 1.4, and others who experienced no acute symptoms had a mean long COVID symptom of 0.7.

In the Pediatric Quality of Life (PedsQL) questionnaire, a list of the 23 most common long COVID symptoms may affect the outcome. Preexisting comorbidities were found to be lesser in the case group. Overall, it was found that the participants from the case group had a higher number of symptoms that lasted longer than the participants in the control group. These were speculated to be the long-lasting complications of SARS-CoV-2 infection.

In general, participants in the case group had worse outcomes – related to generic symptoms, quality of life and psychological impacts, with a recall time of 2-4 weeks. However, the control group participants exhibited worse effects than the case group regarding mood swings, rashes, dry lips, periorbital dark circles, and greater fear and anxiety related to the infection that affected their daily lives. Baseline demographic and clinical profiles might have led to these findings.

On the other hand, the two groups of patients did not have differences in sick days and school absences. Furthermore, 47.8% of participants reported at least one new symptom within eight weeks after SARS-Cov-2 infection. Interestingly, the number and severity of the symptoms seemed to decrease with time.

Furthermore, it was observed that females had a higher number of symptoms than males. While both genders reported more anxiety, depression and less life satisfaction during the pandemic. The social and economic burden of COVID -19 was also evident through more long-lasting symptoms and sick leaves from school, which affects parental work as well.

The symptoms of SARS-CoV-2 infection lasted longer in the case group, who also required more sick leave than the control group. However, the quality of life was better in the case group than in the control group.