An age-related accumulation of a signaling molecule may be one culprit behind older adults’ vulnerability to viral pneumonias, according to a Northwestern Medicine study published in the Journal of Clinical Investigation… Macrophages are among the first lines of defense against viral infections in the lung, including influenza and SARS-CoV-2, the virus that causes COVID-19. These cells cling to the walls of the lung, sampling the air and attacking foreign substances or recruiting other immune cells to the site.
