Antibody response to 2-and 3-dose SARS-CoV-2 mRNA vaccination in pediatric and adolescent kidney transplant recipients

Background Additional "booster" doses of mRNA SARS-CoV-2 vaccines have become standard of care for immunosuppressed patients, including kidney transplant recipients (KTR). While these additional doses have been shown to be efficacious in the adult KTR population, there is paucity of data for pediatric and adolescent KTR. Methods We conducted a retrospective single-center observational study to determine the proportion of pediatric and adolescent KTR who seroconverted following two- and three-dose regimens of an mRNA SARS-CoV-2 vaccine series. Results Forty-three pediatric and adolescent KTR at our center received at least two doses of an mRNA SARS-CoV-2 vaccine. Seroconversion was noted in 56% of those who received a 2-dose series and increased to 85% in those who received a third dose. In the 16 patients who did not seroconvert after a two-dose series, 12 (75%) seroconverted following the third dose. No serious adverse effects of immunization were noted. Conclusions Our results demonstrate that additional SARS-CoV-2 vaccine doses are not only safe and efficacious in pediatric and adolescent KTR, but may be necessary to optimize antibody response.