Protection from severe influenza disease relies on cytolytic CD8+ T cells to clear influenza virus from the lungs (McMichael et al., 1983; Grant et al., 2016; Jansen et al., 2019), thus also limiting the inflammatory response to infection (van den Berg et al., 2021) that leads to cardiovascular complications including strokes (Smeeth et al., 2004; Toschke et al., 2009), heart failure (Panhwar et al., 2019; Vardeny and Solomon, 2019), and ischemic heart disease (Smeeth et al., 2004; Barnes et al., 2015; Kwong et al., 2018; Cardoso et al., 2020). The gene discussed is CD8A; the disease is infection.