SARS-CoV-2 Infection and Liver Transplant: How Are We Now?

Background: The Omicron variant of SARS-CoV-2 emerged as a new variant of concern, characterized by high transmissibility and lower severity compared with previous variants, and became the majority variant in the sixth wave in Spain. This study aims to assess the impact of SARS-CoV-2 infection on liver transplant recipients (LTRs) during 2023 in the population of Cantabria. Methods: The study included 295 LTRs undergoing follow-up at the Liver Transplant Unit of the Marqu & eacute;s de Valdecilla University Hospital. Data on patient characteristics, comorbidities, and vaccination schedules were collected. Humoral response to mRNA vaccines was evaluated using IgG antibodies against the S protein and an adequate response was defined as antibody titers of >260 BAU/mL 1 month after the third vaccine dose. Results: In Cantabria, 0.75% of the general population and 7.10% of LTRs were infected with SARS-CoV-2. Most LTRs were men with comorbidities, mainly cardiovascular disease and hypertension. Of the LTRs, 95.2% were fully vaccinated and received 3 doses of the Moderna mRNA vaccine, and all had an adequate response after 4 to 5 doses. Most infections in LTRs were asymptomatic or mild, with lower hospitalization rates. No LTRs required intensive care admission or died owing to SARS-CoV-2 infection. Conclusions: LTRs are targets for SARS-CoV-2 vaccination. The Omicron variant has shown greater transmissibility but causes milder disease in vaccinated LTRs. All vaccinated LTRs showed an adequate response after 4 to 5 doses. Therefore, vaccination protects against severe disease and mortality in LTRs, and booster vaccinations with variant-adapted vaccines are recommended.