Figure 2.

Depletion and repletion of the T-cell blood pool under normal condition and during COVID-19. Under normal, “steady-state” condition (A), persons with shorter telomeres maintain their T-cell blood pool. However, in the face of SARS-CoV-2 infection (B), persons with shorter telomeres might lag in their ability to increase T-cell production (increase in the pace of the T-cell pool repletion—arrow) to match increased T-cell loss due to the infection (increase in the pace of T-cell pool depletion—arrow). This nonsteady condition would result in shrinking of the T-cell pool in proportion to the shorter telomeres. Telomeres are displayed as red caps at the ends of the chromosomes.