A single-center study of 315 pediatric COVID-19 patients and 1,402 children with seasonal flu identified no difference in rates of hospitalization, intensive care unit (ICU) admission, or mechanical ventilation between the two groups.
The retrospective cohort study, published today in JAMA Network Open, compared the clinical characteristics of children diagnosed as having coronavirus from Mar 25 to May 15, 2020, with those diagnosed with flu from Oct 1, 2019, to Jun 6, 2020, at Children's National Hospital in Washington, DC.
Fifty-four of 315 COVID-19 patients (17%) were hospitalized, 18 (6%) of whom were admitted to the ICU. Ten (3%) required mechanical ventilation.
Of 1,402 patients who tested positive for influenza A or B, 291 (21%) required hospitalization (143 [49%] of whom had type A and 148 (51%) of whom had type B). Ninety-eight of 1,402 flu patients (7%) required ICU care, and 27 (2%) needed mechanical ventilation.
There was no significant difference in duration of mechanical ventilation between the two groups of patients (mean, 10.1 days for COVID-19 patients vs 7.0 for flu patients). No patient had both coronavirus and flu.
Cases of flu dropped dramatically after pandemic-related school closures began on Mar 15 and authorities issued stay-at-home orders on Apr 1. The positivity testing rate for flu declined from 22% in mid-March to 0.3% (only one case) from Mar 22 to Jun 6. Two patients with influenza A died; no deaths were reported among COVID-19 or influenza B patients.
Age, symptoms, underlying diseases
Hospitalized COVID-19 patients were older than those hospitalized with influenza A or B (mean, 9.7 vs 4.2 years). Thirty-seven percent of COVID-19 patients were older than 15 years, compared with just 6% of flu patients. While the study population was primarily pediatric, the age range for both groups was wide, at 0.03 to 35.6 years for COVID-19 patients and 0.04 to 40.4 years for flu patients.
Thirty-five of 54 hospitalized COVID-19 patients (65%) had one or more underlying diseases, which was significantly higher than the rate in hospitalized flu patients (121 of 291 [42%]). The most common underlying conditions in COVID-19 patients were neurologic problems related to global developmental delay or seizures (11 of 54 COVID-19 patients [20%] vs 24 of 291 flu patients [8%]).
Both groups had similar rates of asthma, cardiac and blood conditions, and cancer and most often reported symptoms of fever and cough. There was no difference between percentages of patients reporting cough, congestion, sore throat, or shortness of breath.
But compared with flu patients, a higher percentage of hospitalized coronavirus patients reported fever (76% of COVID-19 patients vs 55% of flu patients), diarrhea or vomiting (26% vs 12%], headache (11% vs 3%), body or muscle aches (22% vs 7%), and chest pain (11% vs 3%).
More hospitalized COVID-19 patients had fever, cough, diarrhea or vomiting, and body and muscle aches than those with hospitalized influenza A, while there was no significant difference in those symptoms or in headache and chest pain between coronavirus patients and those with influenza B.
Fall flu vaccinations
The authors said that, given the large percentage of hospitalized COVID-19 patients with underlying conditions, vulnerable people should be vaccinated against flu to prevent severe disease that could require hospitalization going into fall and winter.
Noting the large drop in flu cases and lack of coronavirus-flu coinfections after school closures and stay-at-home orders were issued, they also called for further studies of the potential benefits of such community interventions on reducing rates of infection and easing hospital burdens during disease surges.
Lead author Xiaoyan Song, PhD, MSc, MB, said that the study has important implications for school closure decisions. "We want to assess the quantitative impact of school closures so we can determine at what point the cost of closing schools and staying at home outweighs the benefit of reducing transmission of COVID-19 and burdens on the health care system," she said in a press release from the hospital.