SARS‑CoV‑2 vaccination in liver transplant recipients: factors affecting immune response and refusal to vaccine

The effectiveness of SARS‑CoV‑2 vaccination in liver transplant (LT) recipients varies between reports.

In this study, we analyzed the immune response to the SARS‑CoV‑2 vaccine, factors affecting the response, and reasons for the vaccine refusal.

Among 300 consecutive LT recipients, 75% were vaccinated. The humoralresponse was assessed by the quantitative determination of antitrimeric spike protein‑specific IgG antibodies to SARS‑CoV‑2. Thirty‑four vaccinated patients with prior SARS‑CoV‑2 infection were analyzed separately.

Among 192 LT recipients vaccinated without past natural infection, 69% developed the immune response (median time of 125 days after the second dose). Older age, worse kidney function, and dual immunosuppression negatively affected the humoral response. Mycophenolate mofetil increased the risk of nonresponse (odds ratio [OR], 2.99; 95% CI, 1.45-6.19). The antibody concentration was higher in the first 90 days from the second dose and stable as compared with 90-150 days and over 150 days. LT recipients with prior COVID‑19 presented with a robust immune response (100%). The female sex, living in a rural area, lower body mass index, and younger age (all P <0.05) were associated with the refusal of the vaccine.

The lower immune response in the vaccinated LT recipients than in the general population justifies administering the third dose of the vaccine. However, more data are needed to recommend any therapy modification before the vaccination.