SARS-CoV-2 infected children form early immune memory responses dominated by nucleocapsid-specific CD8+ T cells and antibodies.

This is the third year of the SARS-CoV-2 pandemic, and yet most children remain unvaccinated. COVID-19 in children manifests as mostly mild or asymptomatic, however high viral titers and strong cellular and humoral responses are observed upon acute infection. It is still unclear how long these responses persist, and if they can protect from re-infection and/or disease severity.

Association between obesity and hospitalization in mild COVID-19 adult outpatients in Brazil: a prospective cohort study.

Objective: To evaluate the association between obesity and hospitalization in mild COVID-19 adult outpatients in Brazil.

Methods: Adults with signs and symptoms suggestive of acute SARS-CoV-2 infection who sought treatment in two hospital (public and private) emergency departments were prospectively enrolled. Patients with confirmed COVID-19 at inclusion were followed by phone calls at days D7, D14 and D28.

Impact of rhinovirus on hospitalization during the COVID-19 pandemic: A prospective cohort study.

Background: Although the clinical course of the COVID-19 in adults has been extensively described, the impact of the co-detection of SARS-CoV-2 and rhinovirus on severity outcomes is not understood.

Objectives: This study aimed to compare the risk of hospitalization of outpatients with COVID-19 with and without the co-detection of rhinovirus in southern Brazil. Secondarily, such risk was also compared between all individuals with COVID-19 and those with single rhinovirus infection.

Rhinovirus as the main co-circulating virus during the COVID-19 pandemic in children.

Objective: Changes in the epidemiology of respiratory infections during the restrictions imposed as a response to the coronavirus disease 2019 (COVID-19) pandemic have been reported elsewhere. The present study's aim was to describe the prevalence of a large array of respiratory pathogens in symptomatic children and adolescents during the pandemic in Southern Brazil.

Methods: Hospitalized and outpatients aged 2 months to 18 years with signs and symptoms of acute COVID-19 were prospectively enrolled in the study from May to November 2020 in two hospitals in a large metropolitan area in a Brazilian city.

Y380Q novel mutation in receptor-binding domain of SARS-CoV-2 spike protein together with C379W interfere in the neutralizing antibodies interaction.

We aimed to describe the SARS-CoV-2 lineages circulating early pandemic among samples with S gene dropout and characterize the receptor-binding domain (RBD) of viral spike protein. Adults and children older than 2 months with signs and symptoms of COVID-19 were prospectively enrolled from May to October in Porto Alegre, Brazil. All participants performed RT-PCR assay, and samples with S gene dropout and cycle threshold < 30 were submitted to high-throughput sequencing (HTS).

Diagnostic accuracy of a SARS-CoV-2 rapid test and optimal time for seropositivity according to the onset of symptoms.

Point-of-care serological tests for SARS-CoV-2 have been used for COVID-19 diagnosis. However, their accuracy over time regarding the onset of symptoms is not fully understood. We aimed to assess the accuracy of a point-of-care lateral flow immunoassay (LFI).

Pediatric COVID-19 patients in South Brazil show abundant viral mRNA and strong specific anti-viral responses.

COVID-19 manifests as a milder disease in children than adults, but the underlying mechanisms are not fully characterized. Here we assess the difference in cellular or humoral immune responses of pediatric and adult COVID-19 patients to see if these factors contribute to the severity dichotomy. Children's non-specific immune profile is dominated by naive lymphocytes and HLA-DRCX3CR1 dendritic cells; meanwhile, children show strong specific antibody and T cell responses for viral structural proteins, with their T cell responses differing from adults by having weaker CD8TNF T cells responses to S peptide pool but stronger responses to N and M peptide pools.

Children Have Similar Reverse Transcription Polymerase Chain Reaction Cycle Threshold for Severe Acute Respiratory Syndrome Coronavirus 2 in Comparison With Adults.

Background: The viral dynamics and the role of children in the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are not completely understood. Our aim was to evaluate reverse transcription polymerase chain reaction (RT-PCR) cycle threshold (Ct) values among children with confirmed SARS-CoV-2 compared with that of adult subjects.

Methods: Patients (from 2 months to ≤18 years of age and adults) with signs and symptoms of acute SARS-CoV-2 infection for less than 7 days were prospectively enrolled in the study from May to November 2020.

Low performance of a SARS-CoV-2 point-of-care lateral flow immunoassay in symptomatic children during the pandemic.

Objective: to evaluate the accuracy of an antibody point-of-care lateral flow immunoassay (LFI - Wondfo Biotech Co., Guangzhou, China) in a pediatric population.

Methods: children and adolescents (2 months to 18 years) with signs and symptoms suggestive of acute SARS-CoV-2 infection were prospectively investigated with nasopharyngeal RT-PCR and LFI at the emergency room.

Absence of detection of RSV and influenza during the COVID-19 pandemic in a Brazilian cohort: Likely role of lower transmission in the community.

Background: Respiratory syncytial virus (RSV) and influenza are prevalent seasonal community viruses. Although not completely understood, SARS-CoV-2 may have the same means of transmission. Preventive social measures aimed at preventing SARS-CoV-2 spread could impact transmission of other respiratory viruses as well.