Comprehensive antibody profiling of mRNA vaccination in children

Bartsch, Yannic C; St Denis, Kerri J; Kaplonek, Paulina; Kang, Jaewon; Lam, Evan C.; Farkas, Eva J; Davis, Jameson; Boribong, Brittany; Shreffler, Wayne; Balazs, Alejandro B; Yonker, Lael M; Alter, Galit

With the emergence of SARS-CoV-2 variants, fluctuating mask mandates, and school re-openings, increased infections and disease surged among children recently. Thus, there is an urgent need for COVID-19 vaccines for children of all ages. However, whether young children will respond appropriately to mRNA vaccines remains unclear. Here, we deeply profiled the vaccine-induced humoral immune response in 7-11 year old children receiving the mRNA-1273 vaccine. Vaccinated children induced significantly higher antibody titers and functions compared to naturally infected children. Moreover, we observed comparable SARS-CoV-2 titers and neutralizing activity across variants of concern and superior Fcγ-receptor binding and phagocytic antibodies in children compared to vaccinated adults. Our data indicate that mRNA vaccination elicits robust antibody responses and drives superior antibody functionality in children. One-Sentence Summary mRNA vaccination elicits robust humoral immune responses to SARS-CoV-2 in children 7-11 years of age.