LAUSR

he continued emergence of Omicron variants during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has challenged infection control and posed a risk to individuals with in fl ammatory bowel disease (IBD) despite vaccination. Previous data suggest an attenuated response to vaccination in adult patients with IBD receiving anti – tumor necrosis factor and other immu-nomodulatory therapy. 1,2 We previously observed a blunted antibody response in children and young adults receiving biologics after SARS-CoV-2 infection. 3 Our study demonstrates that SARS-CoV-2 mRNA vaccines induce signi fi cantly lower short-lived cross-reactive neutralizing antibodies against Omicron lineages BA.1, BA.2, and BA.3 in children and young adults with IBD receiving biologics compared with healthy children after a second or third mRNA vaccination. As new SARS-CoV-2 variants emerge, continued determination of neutralizing antibodies after boosters will be needed in these children. One limita-tion of our study is the lack of children and young adults with IBD not receiving biologic therapy. Our data suggest that children, adolescents, and young adults with IBD un-dergoing treatment with biologic agents may bene fi t from a second booster dose of mRNA vaccines to provide suitable protection against the Omicron subvariants.