Researchers discovered a significant correlation between COVID-19 severity and telomere length. Telomeres are structures at chromosome ends that protect DNA. However, as humans age, telomeres shorten until DNA becomes very susceptible to damage. The researchers used HT Q-FISH, a technique that uses fluorescent signals attached to telomeres, to measure telomere length in COVID-19 patients, and they observed increased telomere shortening with increased age. Using a severity scale with values of 1, 2, 3, 4 for mild, moderate, severe, and acute, respectively, the researchers then observed an indirect relationship between telomere length and COVID-19 severity as well as a direct relationship between age and COVID-19 severity. Women were also found to have longer telomeres than men. The researchers hypothesized that infected individuals with shorter telomeres have an impaired regenerative response of their lung cells, and they believe future strategies like activation of telomerase, an enzyme that relengthens telomeres, are particularly attractive to improve patient outcomes.