Association of Age With SARS-CoV-2 Antibody Response

Abstract

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged in December 2019 and has caused more than 102 million confirmed cases worldwide as of January 31, 2021.¹ Despite intensive study throughout the scientific and medical communities, many clinical and biologic aspects of the disease, especially in the pediatric population, have not yet been elucidated. As data emerged from the initial outbreaks in China, the number of COVID-19 cases in children appeared to be low, with reports indicating that less than 1% were patients younger than 10 years, 1.2% were aged between 10 and 19 years, and only 9 patients were infants with mild symptoms.² In the United States, pediatric infection cases comprised only 7% of total cases as of August 2020.^2,3 The US Centers for Disease Control and Prevention (CDC) reported that, as of September 19, 2020, only 4.1% of the nationally confirmed COVID-19 cases were in school-aged pediatric patients (aged 5-17 years).⁴ Although the causes of these differences remain unclear, most children with SARS-CoV-2 infection are either asymptomatic or exhibit mild symptoms^5-7 and have a low risk of developing severe respiratory disease.^8,9 The CDC reported that the average weekly incidence of COVID-19 cases among adolescents aged 12 to 17 years was approximately twice that of children aged 5 to 11 years.⁴ Only a relatively small number of pediatric patients have experienced severe disease during the acute phase of COVID-19. However, these patients are at risk of severe complications from multisystem inflammatory syndrome in children (MIS-C), an emerging entity thought to occur as sequelae to acute SARS-CoV-2 infection.^10,11 Thus, there appears to be differences in pathophysiologic responses to SARS-CoV-2 based on age.