Though no pathognomonic findings can distinguish EVALI from COVID-19, we noted some differentiating features. First, COVID-19 often leads to normal or low WBC counts often with lymphopenia.3 , 9 In contrast, most patients with EVALI present with leukocytosis,5 , 6 as did 11 of 12 of patients (92%) here (mean WBC, 15.3 k/uL); thus, the patient with leukopenia appears more likely to have COVID-19. Second, a wide age of discrepancy exists between “typical” EVALI and patients with COVID-19. Youths who become severely ill from COVID-19 are relatively uncommon, and EVALI suspicions should rise in the young patient who vapes and presents with respiratory failure. One cannot, however, use age as the sole discriminator between diseases because EVALI can afflict older patients and be morbid.1 Repeated efforts at obtaining a vaping history remain key in making the diagnosis. Third, the administration of systemic corticosteroids appears helpful because both are a therapeutic and diagnostic endeavor. Whereas experts debate the utility of corticosteroids in COVID-19 pneumonia,10 case series suggest their utility in treating EVALI, and we recognize that some patients have a clinical phenotype comparable with eosinophilic pneumonia.2 , 5 In patients with indistinguishable clinical features, we found improvement within 1 to 3 days with corticosteroids to be highly suggestive of EVALI. We recommend a short course of moderate-dose corticosteroids (prednisone 40-60 mg for 5-10 days) when the diagnosis of EVALI seems probable.