The comprehensive clinic, laboratory, and instrumental evaluation of children with COVID-19: a 6-months prospective study

Objectives: To perform a comprehensive clinic, laboratory, and instrumental evaluation of children affected by coronavirus disease (COVID-19). Methods: Children with a positive result of nasopharyngeal swab for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) underwent laboratory tests, anal and conjunctival swab, electrocardiography, lung, abdomen, and cardiac ultrasound. Twenty-four-hour ambulatory blood pressure monitoring was performed if abnormal basal blood pressure. Patients were followed-up for 6 months. Results: Three hundred and sixteen children were evaluated; 15 were finally included. Confirmed family member SARS-CoV-2 infection was present in all. Twenty-seven percent were asymptomatic. Anal and conjunctival swabs tests resulted negative in all. Patients with lower body mass index (BMI) presented significantly higher viral loads. Main laboratory abnormalities were: lactate dehydrogenase increasing (73%), low vitamin D levels (87%), hematuria (33%), proteinuria (26%), renal hyperfiltration (33%), and hypofiltration (13%). Two of the patients with hyperfiltration exhibited high blood pressure levels at diagnosis, and persistence of prehypertension at 6-month follow-up. No abnormalities were seen at ultrasound, excepting for one patient who exhibited B-lines at lung sonography. Immunoglobulin G seroconversion was observed in all at 1-month. Conclusions: Our study confirm that intra-family transmission is important. The significant higher viral loads recorded among patients with lower BMI, together with low vitamin D levels, support the impact of nutritional status on immune system. Renal involvement is frequent even among children with mild COVID-19, therefore prompt evaluation and identification of patients with reduced renal function reserve would allow a better stratification and management of patients. Seroconversion occurs also in asymptomatic children, with no differences in antibodies titer according to age, sex and clinical manifestations.