Driven by T helper 2 (Th2) cells and T2 cytokines, such as interleukin 4 (IL-4), IL-5, and IL-13, the T2-high asthma endotype involves eosinophils, which may provide partial protection against COVID-19 by suppressing T1 inflammatory responses and cytokine storms. The gene discussed is IL4; the disease is asthma.