Although children generally have mild or asymptomatic SARS-CoV-2 infection, there was limited evidence for children with cancer prior to this large cohort study. A global registry involving 131 institutions in 45 countries captured data on 1500 children <19 years old with cancer or a haematopoietic stem-cell transplant who developed COVID-19 between 15 April 2020 and 1 February 2021.1 Of 1319 patients with complete 30-day follow-up, 259 (19.9%) had severe or critical SARS-CoV-2 infection and 50 (3.8%) died. Remdesivir was administered in 65 (16·8%) patients receiving chemotherapy. Factors associated with severe or critical illness on multivariable analysis were low-income or lower-middle-income country (odds ratio (OR) = 5.8, 95% confidence interval (CI) 3.8–8.8) or upper-middle-income (OR = 1.8, 95% CI 1.3–2.3) compared with high-income countries; age 15–18 years (OR = 1.6, 95% CI 1.1–2.2) lymphopaenia ≤300 per mm3 (OR = 2.5, 95% CI 1.8–2.3); neutropenia ≤500 per mm3 (OR = 1.8, 95% CI 1.3–2.4); and intensive treatment (OR = 1.8, 95% CI 1.3–2.3). Cancer-directed therapy was modified in 609 (55.8%) of 1092 patients receiving active oncological therapy and was more likely when they presented with COVID-19 symptoms, had other co-morbidities, when the primary diagnosis was other haematological malignancy (Fig. 1), and when the child came from an upper-middle-income country.

Disease severity by cancer type. (a) Number and proportion of patients with specified disease severity in all diagnoses. (b) Number of patients with specified disease severity by cancer type. (c) Proportion of patients with specified disease severity by cancer type. (), Critical; (), severe; (), moderate; (), mild; (), asymptomatic.