We analyzed antigen-specific CD8+ T cells from a longitudinal cohort of COVID-19 patients with varying acute disease severities as quantified through the WHO ordinal scale (Table S1.1).16,17 To measure patient responses across time, blood samples were taken at diagnosis (T1), several days after infection (T2), and during convalescence 2–3 months post-initial infection (T3). The gene discussed is CD8A; the disease is infection.