P16.04: Seroprevalence of SARS-CoV-2 Antibodies Following Vaccination Amongst Renal Transplant Recipients: A Single Centre-Experience

Aims: Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) poses significant increased mortality in patients undergoing solid organ transplantation. Several vaccines have emerged attempting to mitigate the effects of SARS-CoV-2 amongst vulnerable patient cohorts. This study evaluated the seroconversion rate to SARS-CoV-2 vaccination and antibody persistence following renal transplantation and commencing immunosuppression therapies. Methods: 39 patients received a renal transplant between 17/03/21 – 18/11/21. All patients received 2 doses of Pfizer-BioNTech (BNT162b2) or Oxford/AstraZeneca (AZD1222) vaccination prior to renal transplant. Serum antibodies were tested for pre renal transplant. Further antibody tests were performed at 1 and 3 months respectively. Results: The mean recipient age was 48.1 years (range 18-74 years). All recipients received the second vaccine dose at least 6 weeks pre-transplant. Serum antibody persistent was best appreciated following the Pfizer-BioNtech vaccination (100% at 3 months). Comparatively, diminished antibody response was observed in recipients receiving the Oxford/Astrazeneca vaccine (84% at 3 months). Of the four non-responders post Oxford/Astrazeneca vaccination, 2 had failing transplants (on IS). One recipient developed antibodies at 1 month following the Oxford/AstraZeneca regimen: This may have been secondary to natural exposure or an initial false negative result. There were no acute SARS-CoV-2 infections amongst the cohort. No adverse vaccine-related outcomes were observed. Conclusions: This study suggests vaccination is an effective measure for obtaining SARS-CoV-2 serum antibodies amongst pre-transplant patients. Limited data suggests that pre-existing IS may be an inhibitory factor in relation to vaccination efficacy. Higher seroconversion rates were observed following Pfizer-BioNtech vaccination. Larger scale studies over longer periods are required to investigate antibody persistent in such patients.