Enhanced SARS-CoV-2 BA.2.86 Neutralization After BA.5 Infection in Vaccinated Kidney Transplant Recipients.

Area of Science:

• Immunology
• Transplantation
• Infectious Diseases

Background:

• mRNA vaccines significantly reduce SARS-CoV-2 mortality in the general population.
• Effectiveness of mRNA vaccines in kidney transplant (KTx) recipients remains unclear.
• KTx recipients are a vulnerable population with potentially altered immune responses.

Purpose of the Study:

• To compare disease severity and seroconversion rates after SARS-CoV-2 infection in vaccinated versus unvaccinated KTx recipients.
• To evaluate the antibody response, including IgG and neutralizing antibodies, in KTx recipients post-infection.
• To assess the impact of Omicron variants (BA.5 and BA.2.86) on antibody titers in vaccinated KTx recipients.

Main Methods:

• Cohort study comparing 30 vaccinated and 8 unvaccinated KTx recipients infected during Omicron phases (Feb 2022-Sep 2023).
• Measurement of anti-SARS-CoV-2 spike protein IgG antibodies (cutoff 1.0 AU/mL).
• Investigation of antibody titers and neutralizing capacity against BA.5 and BA.2.86 in 10 vaccinated KTx recipients before and after BA.5 infection.

Main Results:

• Unvaccinated KTx recipients had a significantly higher incidence of moderate disease (P = .004).
• Median antibody titers post-infection were significantly higher in vaccinated (244.5 AU/mL) versus unvaccinated (<1 AU/mL) KTx recipients (P < .0001).
• Vaccinated KTx recipients showed significant increases in IgG and neutralizing antibody titers against BA.5 and BA.2.86 post-infection (P = .004, P = .002, P = .016, respectively).

Conclusions:

• Vaccinated KTx recipients demonstrated an antibody boost post-SARS-CoV-2 infection, unlike unvaccinated individuals who had no increase and more severe disease.
• KTx recipients acquired neutralizing activity against Omicron BA.2.86 following BA.5 infection.
• mRNA vaccination is recommended for KTx recipients to improve immune response and reduce infection severity.