Table 3.

Pediatric cases with long‐COVID as treated by CB, EL, and LvdS

		Patient 1		Patient 2		Patient 3		Patient 4		Patient 5		Patient 6
Age/gender		11 years/M		13 years/F		13 years/M		4 years/M		17 years/M		17 years/F
Medical history		Asthma (2010) Pneumonia Eczema		Asthma (2017) Pneumonia		History of eczema (2007) RSV bronchiolitis		Cow's milk allergy		Asthma Allergic rhinitis Scoliosis Autistic spectrum disorder		Breast reduction
Acute COVID		March 2020		March 2020		August 2020		March 2020		March 2020		September 2020
Long‐COVID consult date		December		December		October		August		September		November
Symptoms of acute COVID‐19		Fever Shortness of breath Thoracic pain		Fever Shortness of breath Thoracic pain headache		Coughing Anosmia (3 weeks)		Fever Runny nose Shortness of breath Fatigue Dizziness Stomach ache Change in bowel habits Skin rashes Generalized myalgia		Fever Dyspnea		Cardiac palpitations Generalized myalgia Balance problems Changes in bowel habits Fatigue Shortness of breath
Hospitalization		No		No		No		No		No		No
Initial treatment		Salbutamol (with effect), fluticasone propionate		Salbutamol (no effect)		None		Broad‐spectrum antibiotics		Fluticasone/salmeterol & Physiotherapy		None
Infection source		Parents (medical history)		Parents (medical history)		Parents (RT‐PCR positive)		Parents (RT‐PCR positive)		Unknown		Unknown
Symptoms of long‐covid		Fatigue Thoracic pain Shortness of breath Coughing Dizziness Thoracic palpitations (Severe) headaches		Fatigue Shortness of breath Thoracic pain Dizziness Nausea Light‐headed Headaches		Fatigue Cognitive dysfunction Weight loss Headaches Exercise intolerance		Fever (intermittent) Fatigue Change in bowel habits Abdominal pain Difficulties breathing Skin rashes Generalized pain		Shortness of breath Fatigue Thoracic pain Coughing		Thoracic pain Fatigue Cardiac palpitations Abdominal pain and abnormal stool Headaches Dizziness
Missing school		Yes		Yes		Yes		n/a		Yes		Yes

			Patient 1		Patient 2		Patient 3		Patient 4		Patient 5		Patient 6
COVID test	PCR		Not done		Not done		Not done		Not done		Negative		Positive
	Serology results		Negative		Negative		Positive		Negative		Positive		Not done
Blood tests	Full blood count		Not done		Normal		Normal		Normal		Normal		Normal
	Inflammation markers		Not done		ESR 20 mm/h CRP 10 mg/L		Normal		Normal		Normal		Normal
	kidney function		Not done		Normal		Normal		Normal		Normal		Normal
	liver function		Not done		Normal ALP 345 U/L (high)		Normal		Not done		Not done		Normal
	thyroid function		Not done		Not done		Normal		Normal		Not done		Not done
	Other		Not done		H. pylori in feces negative		Feces TFT negative Serology for EBV negative IgG CMV positive Normal lymphocyte subsets		Celiac disease excluded normal 25OH‐VitD 2 + 3 PCR for SSYC and parasites negative in feces		Fecal calprotectin level: normal.		Normal electrolytes Normal blood gas Normal PT‐INR Normal d‐dimer Negative pregnancy test
Cardiac evaluation	ECG/Holter		Right axis deviation (135°)		Normal		Normal (stress ECG: normal)		Incomplete right bundle branch block  (no earlier ECG available) Holter: normal sinus rhythm. Sinus tachycardia at time of complaints		Normal		Negative T wave in V3 and III (ECG before COVID‐19 showed a negative T wave in II, but not in V3)
	Echocardiogram		Normal		Not done		Normal		Normal		Not done		Not done
Pulmonary evaluation	CT‐thorax		Not done		Not done		Normal		Not done		Normal		Normal
	Chest X‐ray		Not done		Not done		Not done		Normal		Not done		Not done
	Flow‐Volume		FVC 84% and 97%, FEV1 81% and 99% before and after administration of salbutamol		FVC 102% and FEV1 102.4% after salbutamol		FVC 81% and FEV1 81% after salbutamol		Not done		FVC 90% and FEV1 93% after salbutamol		FVC 80% and FEV1 87% after salbutamol
	Pattern		Obstructive curve		Normal		Normal				Normal		Normal
	Reversibility		Fully reversible		No		No				No		No
	Body plethysmography		Not done		Not done		TLC 76%, RV 74%		Not done		Normal		TLC 88%; RV 86%
	CO diffusion capacity		Not done		Not done		Normal		Not done		Normal		Normal (111%)
Exercise testing			Not done		Treadmill test: maximum heart frequency 173/min O2 saturation: 97%–99%. Dyspnea in line with dysfunctional breathing		CPET: VO2 max: 24 ml/min kg (51%), HF max: 163/min. RER 1.18: conclusion: dysfunctional breathing and reduced physical fitness, no circulatory nor ventilator abnormalities.		Not done		Treadmill test: Anxiety during testing with hyperventilation due to exhaustion. No signs of exercised induced bronchoconstriction, SaO2 reduced to 90% while exercising.		Not done

Abbreviations: ALP, alkaline phosphatase; CMV, cytomegalovirus; CPET, cardiopulmonary exercise testing; EBV, Ebstein Barr Virus; ECG, electrocardiogram; ESR, erythrocyte sedimentation rate; FEV1, forced expiratory volume in 1 s; FT4, free thyroxin fraction; FVC, forced vital capacity; HF, heart frequency; INR, International Normalized Ratio; N/a, not applicable; O₂, oxygen; RER, respiratory exchange rate; RV, residual volume; SSYC, Shigella, Salmonella, Yersinia, Campylobacter; TFT, triple feces test; TLC, total lung capacity; TSH, thyroid stimulation hormone; VO₂ max, maximum oxygen absorption.