Humoral and cellular immunogenicity of a fourth dose BNT162b2 in children with chronic kidney diseases

Abstract

Background. Children with chronic kidney disease (CKD) are at risk of severe complications after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and are recommended to receive vaccine boosters. Although coronavirus disease 2019 (COVID-19) boosters are effective in providing immune responses among healthy children, data on the use of a fourth dose among children with CKD are limited. Methods. We prospectively investigated the immunogenicity and safety of a fourth dose of BNT162b2 in children with CKD. Dosages were 0.1 mL and 0.3 mL for children aged 5–11 years and 11–18 years, respectively. Humoral and cellular immunogenicity was assessed at pre-dose 4, and at 1 and 6 months post-dose 4. Results. Twenty-one children, with a median age of 14.0 years, were included for evaluation. A fourth dose of BNT162b2 elicited significant increases in humoral spike receptor–binding domain immunoglobulin G levels and T-cell responses. Antibody responses were significantly lower among kidney transplant recipients or children receiving calcineurin inhibitors than other CKD children at 1 month post-dose 4. Breakthrough COVID-19 occurred in three children after the fourth dose, and one was hospitalized. One child developed mild gross hematuria 1 day after the fourth dose, which spontaneously resolved. The overall safety profile was acceptable. Conclusions. A fourth dose of BNT162b2 was immunogenic and safe in children with CKD.