Laura W. Musselwhite, MD

Boulad and colleagues report rates of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among children with cancer and their caregivers treated at a large tertiary care referral center in New York City — a global epicenter of the pandemic — between March 10 and April 12. This information is critically important to inform cancer care in the COVID-19 era.

As the authors note, the study faces limitations reporting retrospectively on an emerging pathogen in the context of a global pandemic that is just beginning. Nevertheless, there is valuable information to be gleaned. Among 178 unique pediatric patients tested for SARS-CoV-2 using an RT-PCR assay, 11.2% were infected, while 17.6% of 74 adult caregivers tested were infected. For asymptomatic pediatric patients and adult caregivers without known exposures, infection rates were 2.5% and 14.7%, respectively.

These data suggest that either children may be less prone to infection which has been reported in other studies; that they are less likely to be exposed than their adult caregivers, or that they may clear the virus more quickly. Serologic testing could better inform these hypotheses and would have important epidemiologic and clinical implications.

The authors also note that males were more likely to test positive than females (15.9% vs. 4.2%), which has been reported by others, and that only one symptomatic patient required hospitalization. A small sample size makes it difficult to draw definitive conclusions on these observations, which are notable and deserve further study.

Notably, the authors do not differentiate between individuals with symptomatic COVID-19 infection and those with asymptomatic infection. Additionally, viral load, time to viral clearance and comorbidities were not reported, including cancer type and whether patients were receiving an immunosuppressive therapy or were under surveillance. In the case of other respiratory viruses, including SARS-CoV-1 and influenza, whether a person develops mild disease or pneumonia depends not only on how much virus is in their lungs but also their immune response and general health.

Of importance, 26 states in the U.S. are now reporting increasing cases of a multisystem inflammatory syndrome in children (MIS-C), with a case definition from the CDC suggesting exposure to or test positivity for SARS-CoV-2 within the preceding 4 weeks. The cross-sectional, retrospective nature of this study would not capture this clinical disease should it develop or patient outcomes following a prolonged duration of cancer treatment during a pandemic that will continue for the foreseeable future.  

Robust research efforts to address COVID-19 in adults with cancer are needed and underway, including the NCI COVID-19 in Cancer Patients Study (NCCAPS), which will be expanded to children with cancer soon. Multicenter, prospective cohort studies will be essential to understand how cancer treatment and outcomes are affected by the virus. Until then, we have to know that we do not know what we do not know — and reflect on this important article as the first of its kind, with guarded optimism of the virus’s effects on children being treated for cancer, while leveraging these findings to inform broader population-based work.