Post-acute COVID-19 outcomes in children with mild and asymptomatic disease.

Data on the clinical outcomes of children with COVID-19 are scarce, particularly in those with asymptomatic and mild disease.1, 2 Studies involving adults suggest that long-term multisystem sequelae and complications can occur, even with mild COVID-19. We aimed to describe medium-term clinical outcomes 3–6 months after diagnosis in children with COVID-19 presenting to a tertiary paediatric hospital.

We followed children (aged ≤18 years) at a dedicated COVID-19 follow-up clinic at the Royal Children's Hospital (RCH) in Melbourne, Australia, between March 21, 2020 and March 17, 2021. Children who tested positive for SARS-CoV-2 at the RCH or externally between March 21 and Oct 28, 2020, were referred to this clinic.

A standardised clinic proforma was used to collect information on acute COVID-19 symptoms, transmission risk factors, medical history, and post-acute COVID-19 symptoms (eg, dyspnoea, fatigue, rash, or abdominal pain; appendix pp 1–2). Acute disease severity was classified according to WHO criteria. Data were extracted from the RCH electronic medical record. This study was approved by the RCH Human Research and Ethics Committee (HREC QA/63103/RCHM-2020).

A total of 171 children from 137 households attended the clinic (appendix p 3). Most cases of COVID-19 (136 [80%] of 171 children) were identified between July and August, 2020, corresponding with the epidemiological peak in Melbourne during this period. There have been 3285 reported cases of COVID-19 in children and adolescents (aged 0–19 years) in Victoria to date (March 17, 2021).

Our cohort comprised of 171 children (median age 3 years [IQR 1–8]): 90 (53%) boys and 81 (47%) girls. Most children had mild disease (100 [58%]) or were asymptomatic (61 [36%]), and nine (5%) children had moderate disease. The few hospital admissions (14 [8%] children) were generally brief and were for observation or fluid rehydration. One (1%) child with complex congenital heart disease had severe COVID-19 pneumonitis with acute respiratory failure (appendix p 3). Two (1%) children had post-acute COVID-19 inflammatory conditions temporally associated with SARS-CoV-2: a 7-year-old child with paediatric multisystem inflammatory syndrome who required intensive care management, and an 11-month-old child with Kawasaki disease.

Follow-up data at 3–6 months were available for 151 (88%) of 171 children, of whom 54 (36%) were asymptomatic and 97 (64%) were symptomatic (ie, with mild, moderate, or severe disease) with acute COVID-19. 12 (8%) children had post-acute COVID-19 symptoms, all of whom were symptomatic with acute COVID-19 (table ). The most common post-acute COVID-19 symptoms were mild post-viral cough (six [4%] of 151 children), fatigue (three [2%] children) or both post-viral cough and fatigue (one [1%] child). The duration of post-viral cough ranged from 3 weeks to 8 weeks and of post-viral fatigue ranged from 6 weeks to 8 weeks from the time of symptom onset. At the most recent review in March, 2021, all 151 children had returned to their baseline health status and post-acute COVID-19 symptoms had resolved. Follow-up data for 20 children were not available; seven (35%) of these children had asymptomatic COVID-19.

Table

Demographic and clinical characteristics of children with post-acute COVID-19 symptoms

		Children (n=12)
Sex		..
	Male	7 (58%)
	Female	5 (42%)
Age, years		..
	Mean	3·7 (3·5)
	Median	2 (1–7)
Age group, years		..
	0–2	8 (67%)
	6–12 years	4 (33%)
	13–18 years	0
Comorbidities		3 (25%)
	Congenital cardiac disease	1 (8%)
	Chronic respiratory condition	2 (17%)
Symptom duration, days		..
	Mean	14·6 (12·8)
	Median	11·5 (3·5–25·5)
Acute disease severity		..
	Asymptomatic	0
	Mild disease	11 (92%)
	Moderate disease	0
	Severe disease	1 (8%)
Admitted to hospital*		6 (50%)
	For observation	2 (17%)
	For fluid rehydration	1 (8%)
	Received intensive care unit care*	3 (25%)
Post-acute COVID-19 symptoms		..
	Post-viral cough	6 (50%)
	Fatigue	3 (25%)
	Both cough and fatigue	1 (8%)
	Inflammatory conditions	2 (17%)

Data are n (%), mean (SD), or median (IQR).

All hospital admissions were for acute COVID-19 illness except for two children who were admitted to the intensive care unit due to post-acute inflammatory conditions.

These findings contrast those of studies of COVID-19 in adults, which have identified multisystem complications and a higher prevalence and severity of persistent symptoms. Common complications in adults are respiratory sequelae and persistent fatigue (eg, residual dyspnoea ranging from 11% to 43% and fatigue ranging from 35% to 64%). In our paediatric cohort, full recovery occurred within weeks of acute symptom onset and reported symptoms were mild in severity.

This study was done at a single centre in a metropolitan tertiary paediatric hospital with predominantly young (median age 3 years [IQR 1–8]) children, which could limit the generalisability of results. Our cohort included a large proportion of children with asymptomatic infection (61 [36%] of 171 children), which reflects state government testing guidelines for asymptomatic close contacts of individuals with confirmed COVID-19.

Follow-up was limited to 3–6 months, with outcomes measured with clinical assessments, apart from for two children with post-acute COVID-19 inflammatory conditions who had echocardiograms. As most post-acute COVID-19 symptoms were mild in severity, objective evaluation with lung function tests, a chest CT scan, or both, was not done.

Data on the long-term effects of COVID-19 in children and adolescents are needed, and such data should ideally be nationally representative and include broader demographics. Ongoing follow-up of paediatric patients with COVID-19, including assessment of mental health outcomes, is needed to comprehensively describe long-term outcomes in this population.

We declare no competing interests. DS, ST, and NC designed the study. DS and ST extracted and analysed the data. DS drafted the initial manuscript. All authors interpreted the data and reviewed and revised the manuscript. We thank Kate Dohle, Alissa McMinn, and Isabella Overmars from the Infection and Immunity Theme, Murdoch Children's Research Institute (Melbourne, VIC, Australia).