Prevalence of SARS-CoV-2 in Children Identified by Preprocedural Testing at 5 US Children's Hospital Systems.

Background: The burden of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in asymptomatic children was initially presumed to be high, which influenced hospital, school and childcare policies. Before vaccines were widely available, some hospitals implemented universal preprocedural SARS-CoV-2 polymerase chain reaction testing on asymptomatic patients. Understanding SARS-CoV-2 prevalence in asymptomatic children is needed to illuminate the diversity of viral characteristics and inform policies implemented during future pandemics.

Methods: Data were extracted from patient records of outpatient children who were preprocedurally tested for SARS-CoV-2 from 5 US hospital systems between March 1, 2020, and February 28, 2021. Prevalence was determined from positive test results. Adjusted odds ratios (AORs) were calculated using mixed logistic regression with the site as a random effect.

Results: This study analyzed 93,760 preprocedural SARS-CoV-2 test results from 74,382 patients and found 2693 infections (3.6%) from 2889 positive tests (3.1%). Site-specific prevalence varied across sites. Factors modestly associated with infection included being uninsured [AOR, 1.76 (95% confidence interval [CI], 1.45-2.13)], publicly insured [AOR, 1.17 (95% CI, 1.05-1.30)], Hispanic [AOR, 1.78 (95% CI, 1.59-1.99)], Black [AOR, 1.22 (95% CI, 1.06-1.39)], elementary school age [5-11 years; AOR, 1.15 (95% CI, 1.03-1.28)], or adolescent [12-17 years; AOR, 1.26 (95% CI, 1.13-1.41)].

Conclusions: SARS-CoV-2 prevalence was low in outpatient children undergoing preprocedural testing, a population that was predominantly asymptomatic at the time of testing. This study contributes evidence that suggests that undetected infection in children likely did not play a predominant role in SARS-CoV-2 transmission during the early prevaccine pandemic period when the general population was naive to the virus.