Protective Effect of Vaccine Doses and Antibody Titers Against SARS-CoV-2 Infection in Kidney Transplant Recipients

Area of Science:

• Immunology
• Transplantation Medicine
• Virology

Background:

• Kidney transplant recipients exhibit diminished vaccine response and increased severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) risk.
• The efficacy of initial vaccine formulations and antibody levels against SARS-CoV-2 variants in this population is not well-established.

Purpose of the Study:

• To evaluate the association between vaccination status, immune response, and SARS-CoV-2 infection risk in kidney transplant patients.
• To determine the protective effect of antibody titers and cellular immunity against SARS-CoV-2 variants in this vulnerable group.

Main Methods:

• Retrospective analysis of 622 kidney transplant patients' vaccination records and infection outcomes.
• Measurement of anti-spike protein antibody titers and interferon-γ release assay in 181 vaccinated patients.
• Statistical analysis to calculate odds ratios for infection and hospitalization based on vaccination doses and immune markers.

Main Results:

• Vaccination status and infection rates in kidney transplant patients mirrored the general population.
• More than three vaccine doses correlated with reduced SARS-CoV-2 infection (OR=0.65) and hospitalization (OR=0.32).
• Anti-spike antibody titers above 1,689.3 BAU/mL were protective (OR=0.41), while cellular response showed no correlation.

Conclusions:

• Multiple vaccine doses (over three) and high antibody titers offer significant protection against the Omicron variant in kidney transplant recipients.
• First-generation vaccines remain effective in this population, particularly with robust antibody responses.
• Immune response monitoring, specifically antibody titers, is crucial for assessing protection in immunocompromised patients.