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

We evaluated neutralizing antibodies against the Omicron variant and Anti-Spike IgG response in solid organ (SOT) or hematopoietic stem cell (HSTC) recipients after a third dose of BNT162b2 (BNT) CoronaVac (CV) following two doses CV. In total, 95 participants underwent SOT (n = 62; 44 liver, 18 kidney) HSCT 27; 5 allogeneic, 22 autologous) were included from five centers Turkey. The median time between serum sampling was 154 days (range 15 to 381). vaccine-induced antibody responses both IgGs assessed by plaque assay immunoassay, respectively. Neutralizing levels significantly higher transplant patients receiving BNT compared those CV (Geometric mean (GMT):26.76 vs. 10.89; p 0.03 2116 Au/mL 172.1 Au/mL; < 0.001). Solid transplantation recipients, particularly liver showed lower than recipients. Thus, among GMT 91.29 it 15.81 group (p SOT, kidney (GMT: 48.32 11.72) Moreover, very low 10.81) below detection limit (<10) This study highlights superiority as lack should be taken into consideration, countries where inactivated vaccines are available addition mRNA vaccines.