Rapid progression of CD8 and CD4 T cells to cellular exhaustion and senescence during SARS-CoV2 infection.

Risk factors for the development of severe COVID-19 include several comorbidities, but age was the most striking one since elderly people were disproportionately affected by SARS-CoV-2 infection. Among the reasons for this markedly unfavorable response in the elderly, immunosenescence and inflammaging appear as major drivers of this outcome. A finding that was also notable was that hospitalized patients with severe COVID-19 have an accumulation of senescent T cells, suggesting that immunosenescence may be aggravated by SARS-CoV-2 infection.