Monovalent SARS-CoV-2 mRNA Vaccine Does not Boost Omicron-Specific Immune Response in Diabetic and Control Pediatric Patients.

While the immunogenicity of SARS-CoV-2 vaccines has been well described in adults, pediatric populations have been less studied. In particular, children with type 1 diabetes are generally at elevated risk for more severe disease after infections, but are understudied in terms of COVID-19 and SARS-CoV-2 vaccine responses. We investigated the immunogenicity of COVID-19 mRNA vaccinations in 35 children with type 1 diabetes (T1D) and 23 controls and found that these children develop levels of SARS-CoV-2 neutralizing antibody titers and spike protein-specific T cells comparable to nondiabetic children. However, in comparing the neutralizing antibody responses in children who received 2 doses of mRNA vaccines (24 T1D; 14 controls) with those who received a third, booster dose (11 T1D; 9 controls), we found that the booster dose increased neutralizing antibody titers against ancestral SARS-CoV-2 strains but, unexpectedly, not Omicron lineage variants. In contrast, boosting enhanced Omicron variant neutralizing antibody titers in adults.