CD4 and susceptibility to pneumonia measurement: Interestingly, Li et al. revealed that children with SARS-CoV-2 pneumonia have a greater count of CD3+CD8+ lymphocytes and a larger proportion of CD3+ and CD3+CD8+ lymphocytes when compared to children with pneumonia due to respiratory syncytial virus (RSV) (a well-known infection in pediatrics), without significant differences between the two groups in terms of CD4+/CD8+ ratio, CD3+, CD3+CD4+, and CD16+CD56+ lymphocyte counts, or the proportion of CD3+CD4+ and CD16+CD56+ cells [61].