One in six CYPs in SG develop long COVID

In Singapore, about one in six children and young persons (CYPs) developed long COVID, with persistence of ≥1 symptoms 3 months after an acute COVID-19 infection, a survey study suggests.

“The prevalence of at least 1 persistent symptom lasting beyond 3 months in cases was 16.8 percent,” said the researchers, led by Dr Jiahui Li from the KK Women and Children’s Hospital, Singapore. “Reassuringly, about half will recover by 6 months, with prevalence falling to about 1 in 11.” The rate progressively dropped to 8.7 percent at 6 months post-infection.

On multivariate analyses, the odds of developing long COVID were higher among cases (vs controls; adjusted odds ratio [aOR], 2.43; p=0.005) and in males (vs females; aOR, 1.69; p=0.04). However, the latter finding deviates from studies evaluating the link between gender and long COVID risk. [BMC Med 2022;20:465; Lancet Child Adolesc Health 2022;6:230-239; Pediatr Infect Dis J 2021;40:e509-e511; BMC Med 2022;20:244] “More studies in CYPs are needed to confirm the association between gender and long COVID,” the researchers said.

The most common symptoms of long COVID were nasal congestion or runny nose (7.5 percent), persistent cough (7.4 percent), and fatigue (3.0 percent). [Ann Acad Med Singap 2023;52:522-532]

Compared with controls, cases had a higher likelihood of having persistent cough (OR, 3.39; p=0.23) and nasal congestion or runny nose (OR, 2.76; p=0.04). Cases also had a numerically higher overall odds of reporting at least 1 symptom as severe or very severe than controls (OR, 1.49; p=0.30). Older cases (7–8 years) were more likely to develop long COVID than younger ones (0–6 years; aOR, 1.78; p=0.08).

Keep vaccines up to date

Vaccinated cases were less likely to progress to long COVID (aOR, 0.65; p=0.20). “[Albeit lacking statistical significance, this implies that vaccination cuts] the risk of severe COVID-19 infection and [may] confer some protection against long COVID in CYPs. Keeping up with COVID-19 and influenza vaccinations remain important in guarding our health and wellbeing,” noted the researchers in a press release.

“Further studies are required to study the protective effect of ≥3 doses of COVID-19 vaccines on long COVID in children, as the third dose is introduced to [more] CYPs,” they said.

Screening for persistent symptoms is important

In this anonymized online survey, caregivers of CYPs were invited to complete the survey on behalf of their CYPs (median age 6 years). A total of 640 completed responses were evaluated. Of these, 73.6 percent were cases and 26.4 percent were controls. More than 70 percent of the respondents were Chinese.

Cases were CYPs who had SARS-CoV-2 infection confirmed via antigen rapid test or polymerase chain reaction test, while controls were those who have never tested positive since the onset of the pandemic to the point of survey completion. “For our main outcome analysis, we used the research definition of long COVID … ie, a history of confirmed SARS-CoV-2 infection, with ≥1 persistent physical symptoms for a minimum duration of 3 months with an impact on everyday functioning,” the investigators said. [Arch Dis Child 2022;107:674-80]

Apart from the survey’s cross-sectional design, its retrospective and online nature were potential limitations due to probable recall or selection biases. Infections among controls may have been missed despite the stringent testing systems in Singapore. “Self-reported symptoms can also be biased by age since younger children are unable to express their emotional and functional status adequately compared with older children,” they added.

“[Nonetheless,] given the prevalence of long COVID, it is important for physicians to screen for persistent symptoms in CYPs who had the COVID-19 infection so that we can address these symptoms and assess if there are other causes,” the researchers said.

They called for further investigation to identify risk factors for long COVID development among CYPs.