CD8A and COVID-19: Previous studies have reported that recruitment of neutrophils into influenza-infected trachea is essential for CD8+ T cell–mediated immune protection in mice, while aging increases mortality from influenza because of chemokines secreted by senescent alveolar epithelial cells, leading to excessive neutrophil recruitment.17,18 Thus, we suggest that age-related neutrophil recruitment may be why COVID-19 is milder in pediatric patients than in adult patients.