Serologic Responses to COVID-19 Vaccination in Pediatric Kidney Transplant Recipients.

BACKGROUND

There are limited data describing the immune responses to COVID-19 vaccination in pediatric kidney transplant recipients, and expanding upon this information could help inform vaccination strategies in this unique population.

METHODS

We performed a prospective, observational, single-center cohort study using remnant blood samples of pediatric kidney transplant recipients from routine clinic visits to examine longitudinal serological responses after COVID-19 vaccination. We enrolled 61 pediatric kidney transplant recipients who had at least 1 sample available for analysis. Sera or plasma were analyzed for ancestral SARS-CoV-2 and Omicron (B.1.1.529; BA.1) spike IgG and nucleocapsid IgG using a Meso Scale Discovery platform.

RESULTS

One month after a 3-dose COVID-19 vaccination series, the IgG geometric mean titer to the SARS-CoV-2 ancestral spike was 684 binding antibody units/mL (95% confidence interval, 269-1739), but titers waned by 4-6 mo. A fourth dose of the COVID-19 vaccine boosted IgG geometric mean titer to 1606 binding antibody units/mL (95% confidence interval, 868-2972), and titers persisted through 6 mo. IgG titers against Omicron (B.1.1.529; BA.1) were overall lower than ancestral SARS-CoV-2. They were higher in participants with prior infection and were not significantly impacted by receipt of belatacept.

CONCLUSIONS

Additional doses of the COVID-19 vaccine bolstered durable serologic responses in pediatric kidney transplant recipients, and this study broadens our understanding of immune responses to COVID-19 vaccinations in this population.