INTRODUCTION
The current outbreak of coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), started in or around December, 2019, in Wuhan(1). On January 30th, 2020 the World Health Organization (WHO) declared COVID-19 a pandemic health emergency(2). Since then, COVID-19 has continued to spread quickly and has now become the most dangerous pandemic in over 100 years.
An interactive real-time COVID-19 reporting system set up by the Center for Systemic Science and Engineering at Johns Hopkins University(3) shows, as of the time of this writing, more than 3.7 million confirmed cases and over 258,000 deaths worldwide (led by the U.S., with one third of all cases and a third of all deaths). Globally, this corresponds to a ~7% case fatality rate, although rates vary widely among countries and subpopulations.
The first pediatric case in the literature was reported on January 2020 in 10-year-old boy from Shenzhen, China, whose family had visited Wuhan(4). All epidemiological evidence to date suggests that SARS-CoV-2 infection is less severe in children than in adults. In the latest and largest study in the UK, including 16,749 patients hospitalized for COVID-19, only 239 (2%) were <18 years of age (including 139 who were <5 years old)(5). Large studies in Italy and China have also shown very low case-fatality rates in children and adolescents(6). Understandably, most studies have focused on adult populations, with very few studies and reviews in children. Moreover, accumulating data points to risk factors for severity and mortality in adults (e.g. older age, cardiovascular disease, diabetes, cancer, immunosuppression, obesity, tabacco smoking, etc)(5, 6), but there is very scarce evidence on whether or which risk factors exist in children. While COVID-19 is a multi-system disease, it predominantly affects the lungs, and thus it is critically important to understand whether chronic lung diseases place children at higher risk.
The main objective of this study was to identify whether asthma, the most common chronic respiratory disease in children, is a risk factor for SARS-CoV-2 infection or COVID-19 severity in the pediatric population.