Immunogenicity After a Heterologous BNT262b2 Versus Homologous Booster in Kidney Transplant Recipients Receiving 2 Doses of CoronaVac Vaccine: A Prospective Cohort Study

Abstract

Background. Comparative studies of third heterologous doses following the CoronaVac vaccine against coronavirus disease 2019 (COVID-19) in kidney transplant recipients are lacking. Methods. This prospective, single-center cohort study included kidney transplant recipients without previous COVID-19. Patients received a third heterologous (BNT162b2 mRNA) or homologous dose at least 4 wk after 2 doses of the CoronaVac vaccine. Immunoglobulin G antibody response and seroprevalence for neutralizing anti-severe acute respiratory syndrome coronavirus 2 antibodies immediately before and 28 d after third doses were compared between the groups. Results. There were 307 patients in the heterologous group and 777 in the homologous group. Patients in the heterologous group were older (54 versus 50 y; P < 0.0001), with a longer time since transplant (11 versus 6 y; P < 0.0001). Immediately before the third dose, immunoglobulin G seroprevalence (36% versus 34%; P = 0.597) and antibody titers (246 versus 268 AU/mL; P = 0.279) were similar. After booster, seroconversion was higher in the heterologous group (49% versus 32%; P < 0.0001), resulting in a higher seroprevalence (67% versus 55%; P = 0.0003); however, 42% of all patients remained seronegative. Antibody titers after booster in seropositive patients were higher in the heterologous group (7771 versus 599 AU/mL; P < 0.0001). These results persisted after adjusting for confounding variables. Lastly, a similar proportion of patients became seropositive for neutralizing antibodies (98% versus 94%; P = 0.098). Conclusions. In kidney transplant recipients fully vaccinated with CoronaVac, a third dose with an mRNA vaccine produced a higher seroconversion rate and antibody titers than a third homologous dose. However, both boosters achieved equivalent seroprevalence for neutralizing antibodies. The high proportion of still seronegative patients indicates the need for alternative strategies of protection.

BNT162b2 or CoronaVac as the Third Dose against Omicron: Neutralizing Antibody Responses Among Transplant Recipients Who Had Received Two Doses of CoronaVac

“…Solid organ transplantation patients, particularly liver transplant recipients, showed lower antibody levels than HSCT recipients when antibody responses were examined according to the transplantation type. A lower humoral response was not found to be related to the immunosuppressive regimen, contrary to current publications [5][6][7][8] . For BNT recipients of HSCT, all individuals had positive neutralizing antibody titers regardless of the time elapsed after vaccination.…”

“…However, in countries in which only inactivated vaccines were available at the beginning of the pandemic, patients had access to the mRNA vaccine only as the third dose, and studies indicated better immunogenicity after mRNA boosters. Pestana et al reported higher seroprevalence, seroconversion, and IgG antibody values with a booster with BNT after two doses of CV as a primary regimen in kidney transplant recipients 5 . In our study, additional BNT was found to be more effective than CV after two doses of CV were administered 28 days apart regarding the type of transplantation and time passed after vaccination, similar to recent studies 18 .…”

Cowpox to COVID: History of vaccination in the immunocompromised host

“…Other evaluations of transplant recipients demonstrated increase in antibody levels and SARS‐CoV‐2‐specific CD4 T‐cell response after heterologous vaccination with adenovirus vaccine ChAdOx1 followed by mRNA vaccine, 91 whereas other studies have failed to show significant difference between heterologous versus homologous strategies in a retrospective study from England 92 . Comparison of homologous versus heterologous vaccination strategies with CoronaVac inactivated virus vaccine followed by mRNA vaccine demonstrated higher rates of seroconversion in the heterologous group (49% vs. 32%, p < .001) compared with the homogeneous group in a study from Brazil 93 . This heterologous approach may offer benefit over homogeneous CoronaVac administration where even after four doses, only 20% of previously seronegative kidney transplant recipients were found to seroconvert 94 .…”

“…92 Comparison of homologous versus heterologous vaccination strategies with CoronaVac inactivated virus vaccine followed by mRNA vaccine demonstrated higher rates of seroconversion in the heterologous group (49% vs. 32%, p < .001) compared with the homogeneous group in a study from Brazil. 93 This heterologous approach may offer benefit over homogeneous CoronaVac administration where even after four doses, only 20% of previously seronegative kidney transplant recipients were found to seroconvert. 94 A randomized controlled study of over 300 healthy individuals in Germany who had received two doses of ChAdOx compared the impact of heterogeneous mRNA booster compared with homogeneous booster.…”

First Booster of SARS-COV-2 mRNA Vaccine Is Not Associated With Alloimmunization and Subclinical Injury of Kidney Allograft

“…A s the protection provided by 2 doses of an mRNA vaccine substantially wanes over time and with the emergence of new viral variants, 1 administration of booster doses was recommended for kidney transplant recipients (KTRs). [2][3][4] Vaccination-associated immune activation might be associated with allorecognition and graft injury, 5 and safety data in KTRs are insufficient.…”