Since the onset of the pandemic in 2020, older adults have been at high risk for severe COVID-19 illness. However, the underlying mechanisms for this deadly condition have not always been clear. So far, scientists have attributed the increased risks of severe COVID-19 in older adults to dysregulation of the immune system, an age-related tendency towards excessive blood clotting, and a general decline in adaptive immune strength (T and B cells). Researchers at the University of California, San Francisco, examined the evolution of the infection through a large longitudinal clinical study.
Dr. Huan Fan Fan, the lead author of the study, stated, "We assessed aging in relation to the host immune response in the blood and upper airway, as well as in the nasal microbiome." He added that all individuals in the study, regardless of age, were hospitalized due to the coronavirus. Fan identified that age is associated with a weakened ability to eliminate the virus. Older patients were also more likely to experience heightened disturbances in their body's inflammatory and immune responses.
Unlike younger patients, older adults displayed more active innate immune pathways in the genes and inflammatory cytokines (small proteins that convey cellular messages to help direct the body’s immune response), suggesting that aging might disrupt the body’s ability to halt the inflammatory response. Additionally, biomarkers of disease severity, such as Interleukin 6, were most extreme among the older patients.
Fan concluded, "Our study found that aging is associated with impaired virus clearance, dysregulated immune signaling, and persistent, potentially pathological activation of inflammatory genes and proteins," indicating that these new findings may pave the way for treatment methods specifically targeting older individuals. These differences raise the possibility that older adults with COVID-19 may respond differently, and potentially more favorably, to immune therapies directed against certain inflammatory cytokines.
