COVID19 vaccination in liver transplant recipients

Background In December 2019 the new coronavirus, SARS-CoV-2 was identified in Wuhan, China. It rapidly spread all over the world and since March 2020 Austria is affected by this pandemic. This outbreak turned out a serious challenge for the health care systems and workers. The availability of vaccines against SARS-CoV-2 represents the global cornerstone against the pandemic, yet its efficacy particularly in high-risk populations such as patients with chronic liver disease and solid organ (SOT) recipients under immunosuppression remains to be established.

Methods Our university clinic offered vaccination (Biontech/Pfizer) to liver transplant patients. In this study, we compared humoral and cellular immune response of 25 liver transplant recipients and 47 healthy controls. Antibodies were analyzed at the day of the first vaccination (day 0), on the day of the second vaccination (day 28) and four weeks after complete immunization (day 56) using an RBD enzyme-linked immunosorbent assay (ELISA) and different SARS-CoV-2 neutralization assays using wildtype and pseudo-typed viruses. The presence of SARS-CoV-2 specific T cells directed against the spike (S) and nucleocapsid (N) proteins was assessed at day 56 by an interferon gamma release assay (IGRA).

Results The Biontech/Pfizer vaccine induced measurable antibody titers in healthy subjects and in patients after SOT. Titers in both groups were increased after each injection. The absolute levels of antibodies, however were significantly lower in SOT recipients than in controls. Notably, seroconversion occurred in only half of the SOT recipients but in all of the healthy subjects. T cell responses measured by spike protein IGRA were also significantly reduced in SOT recipients.

Conclusion Pfizer Biontech mRNA Covid 19 vaccination induced both reduced humoral and cellular immune responses in SOT recipients compared to healthy controls. Appropriate boosting strategies have to be developed.

Publication History

Article published online:
01 September 2021