ABSTRACT
Background: Liver transplant recipients have a poorer vaccine response than the general population. Real-life data on SARS-CoV-2 vaccination in liver transplant recipients are limited. The objective of this study was to evaluate the efficacy and safety of the vaccine and identify factors associated with vaccine response. Methods: This was a retrospective observational study of consecutive liver transplant recipients attending CHU De Montpellier. Data on the transplantation indication, immunosuppression, vaccine type, and serology 28 days after the last vaccine dose were collected. Serology below 30 BAU/ml (WHO units) defined non-responders, 30-260 BAU/ml low responders, and >260 BAU/ml responders. Results: 494 patients were included between 1 January and 15 March 2021. 366 (74%) patients were vaccinated: 280 with 3 doses, 63 with 2 doses, and 23 with 1 dose. Complete data were available for 234 patients. 164 (70.1%) patients were male, with a mean age of 59±12 years with a mean time to transplantation of 4.9±5.9 years. No serious adverse events were reported. Of 201 (85.9%) patients with complete vaccination and post-vaccination serology, 104 (51.7%) were responders, 45 (22.4%) poor responders, and 52 (25.9%) nonresponders. In multivariate analysis, factors associated with no or low response were vaccination with Vaxzevria alone (HR 6.8 [1.46- 31.67], p=0.046), mycophenolate mofetil (MMF) therapy (HR 2.1 [1.1-3.9], p=0.025), no previous SARS-CoV-2 infection prior to vaccination (HR 3.6 [1.025-12.89], p=0.046), and female gender (HR 2.4 [1.15-4.99], p=0.02). Conclusions: Only half of our patients were vaccine responders after three injections. MMF, female gender, and Vaxzevria vaccination were associated with a poorer response, while previous SARS-CoV-2 exposure was associated with a better response.