https://www.selleckchem.com/products/vx803-m4344.html Objectives Critical cases of coronavirus disease 2019 (COVID-19) are associated with a high risk of mortality. It remains unclear why patients with the same critical condition have different outcomes. We aimed to explore relevant factors that may affect the prognosis of critical COVID-19 patients. Methods Six critical COVID-19 inpatients were included in our study. The 6 patients were divided into two groups based on whether they had a good or poor prognosis. We collected peripheral blood samples at admission and the time point of exacerbation to compare differences in the phenotypes and functions of major populations of immune cells between the groups. Results On admission, compared to patients with poor prognoses, those with good prognoses had significantly higher counts of monocytes (p less then 0.05), macrophages (p less then 0.05), higher frequency of CD3+ CD4+ CD45RO+ CXCR3+ subsets (p less then 0.05), higher frequency of CD14+ CD11C+ HLA-DR+ subset of dendritic cells (DCs) (p less then 0.05), and a lower count of neutrophils (p less then 0.05). At the time point of exacerbation, the proportions of naïve CD4+ T cells (p less then 0.05), Tregs, and Th2 cells in the poor prognosis group were relatively higher than those in the good prognosis group, and CD4+ memory T cells were relatively lower (p less then 0.05). Conclusion According to our results, the poor prognosis group showed a worse immune response than the good prognosis group at the time of admission and at exacerbation. Dysregulation of the immune response affects the outcome of critical COVID-19 patients. This article is protected by copyright. All rights reserved.Respiratory syncytial virus (RSV) is a relevant cause of acute respiratory infection among children. Viral replication and immune conditions may account for severity. RSV viral load (VL) was assessed in 486 children (290 hospitalized and 196 from primary care) attended at São Paulo Hospita