Humoral and cellular immune response to SARS-CoV-2 mRNA BNT162b2 vaccine in pediatric kidney transplant recipients compared with dialysis patients and healthy children.

BACKGROUND: Compared with the general population, the immune response to COVID-19 mRNA vaccines is lower in adult kidney transplant recipients (KTRs). However, data is limited for pediatric KTRs. In this study, we aimed to assess humoral and cellular immune responses to the COVID-19 mRNA vaccine in pediatric KTRs. METHODS: This multicenter, prospective, case-control study included 63 KTRs (37 male, aged 12-21 years), 19 dialysis patients, and 19 controls. Humoral (anti-SARS-CoV2 IgG, neutralizing Ab (nAb)) and cellular (interferon-gamma release assay (IGRA)) immune responses were assessed at least one month after two doses of BNT162b2 mRNA vaccine. RESULTS: Among COVID-19 naïve KTRs (n = 46), 76.1% tested positive for anti-SARS-CoV-2 IgG, 54.3% for nAb, and 63% for IGRA. Serum levels of anti-SARS-CoV-2 IgG and nAb activity were significantly lower in KTRs compared to dialysis and control groups (p < 0.05 for all). Seropositivity in KTRs was independently associated with shorter transplant duration (p = 0.005), and higher eGFR (p = 0.007). IGRA titer was significantly lower than dialysis patients (p = 0.009). Twenty (43.4%) KTRs were positive for all immune parameters. Only four of 11 seronegative KTRs were IGRA-positive. COVID-19 recovered KTRs had significantly higher anti-SARS-CoV-2 IgG and nAb activity levels than COVID-19 naïve KTRs (p = 0.018 and p = 0.007, respectively). CONCLUSIONS: The humoral and cellular immune responses to SARS-CoV-2 mRNA BNT162b2 vaccine are lower in pediatric KTRs compared to dialysis patients. Further prospective studies are required to demonstrate the clinical efficacy of the mRNA vaccine in KTRs. This prospective study was registered in ClinicalTrials.gov (NCT05465863, registered retrospectively at 20.07.2022). A higher resolution version of the Graphical abstract is available as Supplementary information.

BNT162b2 COVID-19 vaccination elicited protective robust immune responses in pediatric patients with inborn errors of metabolism.

Introduction: SARS-CoV-2 infection can lead to a life-threatening acute metabolic decompensation in children with inborn errors of metabolism (IEM), so vaccination is mandatory. However, IEMs can also impair innate or adaptive immunity, and the impact of these immune system alterations on immunogenicity and vaccine efficacy is still unknown. Here, we investigated humoral immune responses to the BNT162b2 mRNA COVID-19 vaccine and clinical outcomes in pediatric IEM patients. Methods: Fifteen patients between 12-18 years of age with a confirmed diagnosis of IEM, and received BNT162b2 were enrolled to the study. Patients with an anti-SARS-CoV-2 IgG concentration >50 AU/mL before vaccination were defined as "COVID-19 recovered" whereas patients with undetectable anti-SARS-CoV-2 IgG concentration were defined as "COVID-19 naïve". Anti-SARS-CoV-2 Immunoglobulin G (IgG) and SARS-CoV-2 neutralizing antibody (nAb) titers were measured to assess humoral immune response. Results: Anti-SARS-CoV-2 IgG titers and nAb IH% increased significantly after the first dose. The increase in antibody titers after first and second vaccination remained significant in COVID-19 naïve patients. Complete anti-SARS-CoV-2 IgG seropositivity and nAb IH% positivity was observed in all patients after the second dose. Vaccination appears to be clinically effective in IEM patients, as none of the patients had COVID-19 infection within six months of the last vaccination. Discussion: Humoral immune response after two doses of BNT162b2 in pediatric IEM patients was adequate and the immune response was not different from that of healthy individuals.

COVID-19 in pediatric patients undergoing chronic dialysis and kidney transplantation.

The study aims to present the incidence of COVID-19 in pediatric patients undergoing renal replacement therapy (RRT) and to compare the severity and outcomes of the disease between the dialysis and kidney transplant (KTx) groups. This multicenter observational study was conducted between 1 April and 31 December 2020 in Istanbul. Members of the Istanbul branch of the Turkish Pediatric Nephrology Association were asked to report all confirmed cases of COVID-19 who were on RRT, as well as the number of prevalent RRT patients under the age of 20. A total of 46 confirmed cases of COVID-19 were reported from 12 centers, of which 17 were dialysis patients, and 29 were KTx recipients. Thus, the incidence rate of COVID-19 was 9.3% among dialysis patients and 9.2% among KTx recipients over a 9-month period in Istanbul. Twelve KTx recipients and three dialysis patients were asymptomatic (p = 0.12). Most of the symptomatic patients in both the dialysis and KTx groups had a mild respiratory illness. Only two patients, one in each group, experienced a severe disease course, and only one hemodialysis patient had a critical illness that required mechanical ventilation. In the entire cohort, one hemodialysis patient with multiple comorbidities died.Conclusion: While most cases are asymptomatic or have a mild disease course, pediatric patients undergoing dialysis and a kidney transplant are at increased risk for COVID-19. What is Known: • In adult population, both dialysis patients and kidney transplant recipients are at increased risk for severe illness of COVID-19 and have higher mortality rate. • Children with kidney transplantation are not at increased risk for COVID-19 and most have mild disease course. • Data on children on dialysis are scarce. What is New: • Pediatric patients undergoing dialysis and kidney transplantation have an increased risk for COVID-19. • Most patients undergoing renal replacement therapy either on dialysis or transplanted develop asymptomatic or mild COVID-19 disease with a favorable outcome.