Researchers from MSK Kids at Memorial Sloan Kettering Cancer Centre (MSK) found that children with cancer are not at a higher risk of being affected by COVID-19. This new research was led by Dr Andrew Kung, chair of MSK Kids and his colleagues.
MSK Kids is one of the largest paediatric cancer programmes in the US with a patient population that includes children, adolescents and young adults with cancer and a small proportion with non-oncological diseases such as bone marrow failure and immune-deficiencies.
Paediatric cancer patients are no more vulnerable than other children to COVID-19 infection or morbidity resulting from COVID-19. Of all children with cancer infected with COVID-19, 95 percent had mild symptoms and did not require hospitalisation. MSK Kids clinicians also tested asymptomatic children with cancer finding only a 2.5% rate of positivity compared to nearly 15% in their adult caregivers. Only half of the children with COVID-19 positive caregivers were themselves also COVID-19 positive.
The researchers also found a very significant sex skewing with the vast majority of COVID-19 infections occurring in males. Together, these results suggest that children with cancer are not more susceptible than other children to infection or symptoms resulting from COVID-19, and that children are not an unrecognized reservoir of asymptomatic COVID-19 infection.
From 10 March through 12 April, 2020, MSK Kids researchers instituted a screening and testing plan to mitigate risk associated with infection with COVID-19. MSK Kids patients were screened for exposure to contacts with known COVID-19 infection or for the presence of symptoms of COVID-19 illness at MSK. Researches performed COVID-19 testing on paediatric patients and their adult caregivers. Of the 178 unique paediatric cancer patients tested, the rate of positivity for COVID-19 was 29.3 percent in children with symptoms, but only 2.5% in asymptomatic children. Of the 20 patients who tested positive for COVID-19, only 3 were female.
Only one patient with COVID-19 illness required non-critical care hospitalisation for COVID-19 associated symptoms. All other paediatric patients had mild disease symptoms and were managed at home. Of the 74 adult caregivers tested, 13 caregivers of 10 patients were found to be positive for COVID-19, including a 14.7% rate of COVID-19 infection in asymptomatic caregivers. Only half of the patients with COVID-19 positive caregivers were themselves also COVID-19 positive, suggesting low infectivity in children despite close household contacts.
While the overall numbers in the study are small, the data confirms that the overall morbidity of COVID-19 illness in paediatric cancer patients is low with only 5% requiring hospitalisation for symptoms of COVID-19 infection; and that the rate of COVID-19 infection among asymptomatic paediatric patients is very low.
“We are encouraged by these latest findings that kids with cancer are not more endangered by COVID-19 and their symptoms are mild like in healthy children,” said Kung, the corresponding author on the study. “These findings allow us to continue lifesaving cancer-directed therapy with standard precautions and safeguards but without heightened concern about adverse effects from COVID-19 infection.”
Introduction: Data on the prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in children,1-4 and in children with cancer specifically have been limited. Less than 1% of cases reported from China were in children younger than 10 years.3 The MSK Kids pediatric program at Memorial Sloan Kettering Cancer Center (MSK) is one of the largest pediatric cancer programs in the US. Starting in mid-March, 2020, we instituted a screening and testing plan to mitigate risk associated with coronavirus disease 2019 (COVID-19).
Methods: On presentation for outpatient or inpatient care, patients were screened for the presence of symptoms of COVID-19 or exposure to contacts with known SARS-CoV-2 infection. We also instituted testing for SARS-CoV-2 using a RT-PCR assay for 3 cohorts of individuals: (1) patients exposed to COVID-19 (screen positive) or with symptoms of infection (symptom positive); (2) asymptomatic patients (symptom negative) prior to deep sedation, myelosuppressive chemotherapy, or admission to the hospital; and (3) caregivers accompanying patients for admission or multiday outpatient chemotherapy. Data for this report were gathered a retrospective research protocol approved by the MSK institutional review board with waiver of informed consent owing to the retrospective and deidentified nature of the data used. Groups were compared using a 2-tailed Fisher exact test.
Results: Between March 10 and April 12, 2020, a total of 335 tests for SARS-CoV-2 were performed on pediatric patients and their caregivers (Table 1). Of the 178 unique pediatric patients (107 male and 71 female) tested (mean [SD] age 11.1 [8.5] years), 20 (11.2%) had positive test results (mean [SD] age 15.9 [6.6] years). Of patients specifically tested for positive screening or symptoms (screen positive or symptom positive), the rate of positivity for SARS-CoV-2 was 29.3%. By comparison, in the 120 asymptomatic patients without known exposure (screen negative and symptom negative) the rate of SARS-CoV-2 positivity was only 2.5% (29.3%; 95% CI, 18.1%-42.7% versus 2.5%; 95% CI, 0.5%-7.1%; P < .001) (Table 1). Of the 20 patients who tested positive for SARS-CoV-2, only 3 were female (Table 2), a significant sex skewing when compared with pediatric patients who tested negative (15%; 95% CI, 3%-38% vs 43%; 95% CI, 35%-51%; P = .02).
Only 1 patient with COVID-19 illness required noncritical care hospitalization for COVID-19 symptoms. Three other patients without significant COVID-19 symptoms were admitted for concomitant fever and neutropenia, cancer morbidity, or planned chemotherapy. All other pediatric patients had mild symptoms and were managed at home.
We also instituted testing of adult caregivers of patients (Table 1). Of the 74 individuals tested, 13 caregivers (17.6%) of 10 patients tested positive for SARS-CoV-2. Notably among 68 asymptomatic and unexposed caregivers (screen negative and symptom negative), 10 tested positive for SARS-CoV-2 (14.7%). Simultaneous detection of virus in patient and caregiver was found in 5 patient/caregiver dyads, whereas 5 patients were negative for virus despite close exposure to caregivers with COVID-19.
Discussion: Although this report is limited by small numbers, the data show that (1) the overall morbidity of COVID-19 in pediatric patients with cancer is low with only 5% requiring hospitalization for symptoms of COVID-19; (2) that the rate of SARS-CoV-2 infection among asymptomatic pediatric patients is very low; (3) that unrecognized SARS-CoV-2 infection in asymptomatic caregivers is a major infection control consideration; and (4) that consistent with the sex difference previously seen in adults with critical disease,5 there is a male bias in SARS-CoV-2 infections in children, suggesting a biological basis in skewed infectivity.
This report suggests that pediatric patients with cancer may not be more vulnerable than other children2-4 to infection or morbidity resulting from SARS-CoV-2. Although the asymptomatic SARS-CoV carrier rate in children in the general population is not known, our testing of 120 asymptomatic pediatric patients with cancer revealed only a 2.5% rate of SARS-CoV-2 positivity. By comparison, we observed a 14.7% rate of SARS-CoV-2 positivity in their asymptomatic caregivers (2.5%; 95% CI, 0.5%-7.1% vs 14.7%; 95% CI, 7.3%-25.4%; P = .002), which closely matches the asymptomatic carrier rate in pregnant women in New York (13.5%).6 Together, our results do not support the conjecture that children are a reservoir of unrecognized SARS-CoV-2 infection.
Farid Boulad, Mini Kamboj, Nancy Bouvier, Audrey Mauguen, Andrew L Kung