Robust antibody responses in children after Pfizer vaccination

Abstract

Abstract SARS-CoV-2 is a devastating global pandemic which has resulted in mass loss of life. It is essential to vaccinate children to achieve herd immunity and prevent community transmission. In addition, the importance of vaccinating children is further illustrated by increasing COVID-19 cases among this age group and the associated Multisystem Inflammatory Syndrome in Children (MIS-C). Children possess a relatively naïve immune system compared to adults. With reopening of schools, relaxation of mask mandates and new emerging viral variants, it is imperative to better understand the magnitude and quality of vaccine induced responses in children, especially in terms of breadth of immunity against emerging viral variants. In the current study we have assessed the humoral response after vaccination in children 11–17 years of age. We found robust responses in children, with Spike and RBD specific antibody titers that were significantly higher than adult vaccinees. In addition, these titers were also much higher than those seen in both convalescent hospitalized pediatric COVID and MIS-C cases. Compared to adults, the pediatric vaccinees showed a similar breadth against current viral variants. Finally, using a live neutralization assay we similarly found that children exhibited higher neutralization titers than adults and that the neutralization titers positively correlated with their RBD binding titers. Overall, our data show that vaccination induces more potent antibody responses in children as compared to adults, with similar breadth against emerging viral variants.