Multiple-cohort study of the elderly to determine the immunological characteristics and pathogenic mechanisms of severe community-acquired pneumonia caused by the low-virulence virus SARS-CoV-2 Omicron variant.

A study published in the journal Cell Discovery investigated the immunological characteristics and pathogenic mechanisms of severe community-acquired pneumonia (Sev-CAP) caused by the low-virulence Omicron variant of the SARS-CoV-2 virus in elderly individuals. The study found that older adults with Sev-CAP had elevated inflammatory and antibody responses but diminished antiviral immunity. They also showed weak antibody neutralization against the Omicron variant. The study revealed impaired functions of innate immune cells and effector T cells in Sev-CAP, as well as an increased proportion of plasmacytes with immunoglobulin hyperproduction. The findings suggest that the Omicron variant can still cause severe outcomes in older adults due to age-related factors and impaired immune responses. [Extracted from the article]