Weak antibody response to 3 doses of mRNA vaccine in kidney transplant recipients treated with belatacept

Chavarot, Nathalie; Morel, Antoine; Leruez-Ville, Marianne; Villain, Estelle; Divard, Gillian; Burger, Carole; Serris, Alexandra; Sberro-Soussan, Rebecca; Martinez, Frank; Amrouche, Lucile; Bererhi, Lynda; Lanternier, Fanny; Legendre, Christophe; Zuber, Julien; Anglicheau, Dany; Scemla, Anne

Poor responses to mRNA COVID-19 vaccine have been reported after 2 vaccine injections in kidney transplant recipients (KTRs) treated with belatacept. We analyzed the humoral response in belatacept-treated KTRs without history of SARS-CoV-2 infection who received 3 injections of BNT162b2-mRNA COVID-19 vaccine. We also investigated vaccine immunogenicity in belatacept-treated KTRs with prior COVID-19 and characterized symptomatic COVID-19 infections after vaccine in belatacept-treated KTRs. Among the 62 belatacept-treated KTRs (36 (58%) males, median age (63.5 years IQR (51-72), without COVID-19 history, only 4 patients (6.4%) developed anti-SARS-CoV-2 IgG with low antibody titers (median 209, IQR (20-409) AU/mL). 71% were treated with mycophenolic acid and 100% with steroids in association with belatacept. In contrast, in all the 5 KTRs with prior COVID-19 history, mRNA vaccine induced strong antibody response with high antibody titers (median 10769 AU/mL, IQR (6410-20069)) after 2 injections. Seroprevalence after 3-vaccine doses in 35 non-belatacept-treated KTRs was 37.1%. 12 KTRs developed symptomatic COVID-19 after vaccination, including severe forms (50% of mortality). Breakthrough COVID-19 occurred in 5% of fully vaccinated patients. Administration of a third dose of BNT162b2 mRNA COVID-19 vaccine did not improve immunogenicity in KTRs treated with belatacept without prior COVID-19. Other strategies aiming to improve patient protection are needed.