Introduction: The data on long COVID in children is scarce since children and adolescents are typically less severely affected by acute COVID-19. This study aimed to identify the long-term consequences of SARS-CoV-2 infection in children, and to compare the persistent symptom spectrum between COVID-19 and community-acquired infections of other etiologies.Methods: This was an ambidirectional cohort study conducted at the Children's Clinical University Hospital in Latvia. The study population of pediatric COVID-19 patients and children with other non-SARS-CoV-2-community-acquired infections were invited to participate between July 1, 2020, and April 30, 2021.Results: In total, 236 pediatric COVID-19 patients were enrolled in the study. Additionally, 142 comparison group patients were also enrolled. Median follow-up time from acute symptom onset was 73.5 days (IQR; 43–110 days) in the COVID-19 patient group and 69 days (IQR, 58–84 days) in the comparison group. Most pediatric COVID-19 survivors (70%, N = 152) reported at least one persistent symptom, but more than half of the patients (53%, N = 117) noted two or more long-lasting symptoms. The most commonly reported complaints among COVID-19 patients included persistent fatigue (25.2%), cognitive sequelae, such as irritability (24.3%), and mood changes (23.3%), as well as headaches (16.9%), rhinorrhea (16.1%), coughing (14.4%), and anosmia/dysgeusia (12.3%). In addition, 105 (44.5%) COVID patients had persistent symptoms after the 12-week cut-off point, with irritability (27.6%, N = 29), mood changes (26.7%, N = 28), and fatigue (19.2%, N = 20) being the most commonly reported ones. Differences in symptom spectrum among the various age groups were seen. Logistic regression analysis showed that long-term persistent symptoms as fever, fatigue, rhinorrhea, loss of taste and/or smell, headaches, cognitive sequelae, and nocturnal sweating were significantly associated with the COVID-19 experience when compared with the controls.Conclusions: We found that at the time of interview almost three-quarters of children reported at least one persistent symptom, but the majority of patients (53%) had two or more concurrent symptoms. The comparison group's inclusion in the study allowed us to identify that symptom persistence is more apparent with COVID-19 than any other non-SARS-CoV-2 infection. More research is needed to distinguish the symptoms of long COVID from pandemic-associated complaints. Each persistent symptom is important in terms of child well-being during COVID-19 recovery.

The total number of COVID-19 positive cases in Latvia has escalated rapidly since October 2020, peaking in late December 2020 and early January 2021. Children generally develop COVID-19 more mildly than adults; however, it can be complicated by multisystem inflammatory syndrome in children (MIS-C). This case study aims were to assess demographic characteristics and the underlying medical conditions, and clinical, investigative and treatment data among 13 MIS-C patients using electronic medical records. All 13 had acute illness or contact with someone who was COVID-19 positive two to six weeks before MIS-C onset. Only five of the 13 were symptomatic during the acute COVID-19 phase. The median age was 8.8 years; 11/13 patients were male, 10/13 had been previously healthy, and all 13 patients tested positive for SARS-CoV-2 by RT-PCR or antibody testing. The most commonly involved organ systems were the gastrointestinal (13/13), hematologic (13/13), cardiovascular (13/13), skin and mucosa (13/13), and respiratory (12/13) ones. The median hospital stay was 13 (interquartile range, 11 to 18) days; 7/13 patients received intensive care, 6/13 oxygen support, and 5/13 received inotropic support. No deaths occurred. During the current pandemic, every child with a fever should have a clearly defined epidemiological history of COVID-19, a careful clinical assessment of possible multiple organ-system involvement, with a special focus on children with severe abdominal pain and/or skin and mucocutaneous lesions.

Background and Objectives: Since the first cases of multisystem inflammatory syndrome in children (MIS-C) in April 2020, the diagnostic challenge has been to recognize this syndrome and to differentiate it from other clinically similar pathologies such as Kawasaki disease (KD) and toxic shock syndrome (TSS). Our objective is to compare clinical signs, laboratory data and instrumental investigations between patients with MIS-C, KD and TSS. Materials and Methods: This retrospective observational study was conducted at the Children’s Clinical University Hospital, Latvia (CCUH). We collected data from all pediatric patients <18 years of age, who met the Centers for Disease Control and Prevention case definition for MIS-C, and who presented to CCUH between December 2020 and December 2021. We also retrospectively reviewed data from inpatient medical records of patients <18 years of age diagnosed as having KD and TSS at CCUH between December 2015 and December 2021. Results: In total, 81 patients were included in this study: 39 (48.1%) with KD, 29 (35.8%) with MIS-C and 13 (16.1%) with TSS. In comparison with TSS and KD, patients with MIS-C more often presented with gastrointestinal symptoms (abdominal pain (p < 0.001), diarrhea (p = 0.003)), shortness of breath (p < 0.02) and headache (p < 0.003). All MIS-C patients had cardiovascular involvement and 93.1% of MIS-C patients fulfilled KD criteria, showing higher prevalence than in other research. Patients with KD had higher prevalence of cervical lymphadenopathy (p < 0.006) and arthralgias (p < 0.001). In comparison with KD and TSS, MIS-C patients had higher levels of ferritin (p < 0.001), fibrinogen (p = 0.04) and cardiac biomarkers, but lower levels of platelets and lymphocytes (p < 0.001). KD patients tended to have lower peak C-reactive protein (CRP) (p < 0.001), but higher levels of platelets. Acute kidney injury was more often observed in TSS patients (p = 0.01). Pathological changes in electrocardiography (ECG) and echocardiography were significantly more often observed in MIS-C patients (p < 0.001). Conclusions: This research shows that MIS-C, KD and TSS have several clinical similarities and additional investigations are required for reaching final diagnosis. All the patients with suspected MIS-C diagnosis should be examined for possible cardiovascular involvement including cardiac biomarkers, ECG and echocardiography.