The most important explanatory variables for pulmonary abnormalities by three unrelated classifiers (C5.0, RF, and glmNet) included preexisting malignancy, multimorbidity, markers of systemic inflammation (IL-6 and CRP), and anti-S1/S2 antibody levels at the 60-day follow-up (Figure 9—figure supplement 4, Figure 9—figure supplement 5, Figure 9—figure supplement 6). This evidence concerns the gene CRP and cancer.