Reduced Humoral and Cellular Immune Response to Primary COVID-19 mRNA Vaccination in Kidney Transplanted Children...

Area of Science:

• Immunology
• Vaccinology
• Pediatrics

Background:

• Limited data exists on COVID-19 mRNA vaccine responses in immunocompromised children.
• Secondary immunodeficiency in children, such as post-kidney transplant, may impact vaccine efficacy.

Purpose of the Study:

• To investigate humoral and T cell responses to BNT162b2 vaccination in immunocompromised children.
• To compare responses between children post-kidney transplant, with glomerulonephritis, and healthy controls.

Main Methods:

• Prospective observational study of children aged 5-11 years.
• Assessed antibody levels and T cell responses (cytokine secretion, activation markers) after primary vaccination.
• Stimulated peripheral blood mononuclear cells (PBMCs) with SARS-CoV-2 spike protein peptides (Wuhan Hu-1 and Omicron BA.5).

Main Results:

• Seroconversion rates were 56% in kidney transplant (KTx) patients vs. 100% in glomerulonephritis (GN) and controls.
• Antibody titers were significantly lower in KTx patients compared to GN patients and controls.
• Humoral response improved in KTx patients after a third dose.
• No significant differences in antigen-specific CD4+ and CD8+ T cell frequencies were observed.
• T cell antiviral cytokine secretion capacity was reduced in KTx patients.

Conclusions:

• COVID-19 mRNA vaccination induces a variable humoral response in immunocompromised children, with lower efficacy in KTx patients.
• While T cell frequency was similar, functional antiviral capacity was diminished in KTx patients.
• Further immunization may be necessary for immunocompromised children to achieve adequate protection.