Telomeres and COVID‐19

The medical, public health, and scientific communities are grappling with monumental imperatives to contain COVID‐19, develop effective vaccines, identify efficacious treatments for the infection and its complications, and find biomarkers that detect patients at risk of severe disease. The focus of this communication is on a potential biomarker, short telomere length (TL), that might serve to identify patients more likely to die from the SARS‐CoV‐2 infection, regardless of age. The common thread linking these patients is lymphopenia, which largely reflects a decline in the numbers of CD4/CD8 T cells but not B cells. These findings are consistent with data that lymphocyte TL dynamics impose a limit on T‐cell proliferation. They suggest that T‐cell lymphopoiesis might stall in individuals with short TL who are infected with SARS‐CoV‐2.