Anti‐SARS‐CoV‐2 spike protein and neutralizing antibodies at 1 and 3 months after three doses of SARS‐CoV‐2 vaccine in a large cohort of solid organ transplant patients

摘要

The immunogenicity of the severe acute respiratory syndrome‐coronavirus 2 (SARS‐CoV‐2) vaccine was improved by the administration of a third dose. The aim of our retrospective study was to assess the evolution of binding and neutralizing antibody concentration until 3?months after the third dose in a large cohort of solid organ transplant (SOT) patients (n?=?872). At 1?month after the third dose, anti‐SARS‐CoV‐2 antibodies were detected by means of enzyme‐linked immunosorbent assay tests in 578 patients (66.3%). In a subgroup of patients, 70% (180 out of 257) had anti‐SARS‐CoV‐2 antibody concentrations ranging from 1.2 to 18?411 binding antibody units (BAU)/ml and 48.5% (115 out of 239) had a neutralizing antibodies titer that can confer clinical protection against SARS‐CoV‐2. Three‐hundred ninety‐three patients out of the 416 (94.5%) who were seropositive at month 1 and were tested at 3?months after vaccination remained seropositive. Between months 1 and 3 after vaccination, binding and neutralizing antibodies concentrations decreased significantly. The proportion of protected patients against the SARS‐CoV‐2 also slightly decreased. In conclusion, this study shows that although two‐third of SOT develop anti‐SARS‐CoV‐2 antibodies after three doses, one‐third of them remain weak or non‐protected. It is important to measure anti‐SARS‐CoV‐2 antibodies to define the strategy that can optimize SOT protection against SARS‐CoV‐2.