ABSTRACT
Background: From January 2022 the Omicron SARS-CoV-2 variant became the dominant circulating variant worldwide, showing increased transmissibility and the ability to evade immunity. Booster vaccinations improved the protective effects of neutralizing antibodies and might have lowered the risk of hospitalization and mortality, as recently observed. Aim: to evaluate the prevalence and outcome of Omicron-related infection in a cohort of liver transplant (LT) recipients. Material and Methods: From January to September 2022, we enrolled in a longitudinal study all LT recipients who became SARS-CoV-2 infected (95% vaccinated;88% receiving a 1st booster dose and 25% a 2nd booster). All patients were included in a protocol of testing anti-spike (a-S) and anti-nucleocapsid (a-N) antibodies titres before/after each dose (Elecsys Anti-SARS-CoV-2, Roche Diagnostic). Diagnostic criteria for SARS-CoV-2 infection were 1) presence of a positive nasopharyngeal swab (NFS) by PCR or antigenic assays or 2) presence of a-N seroconversion (if previously a-N negative). Reinfection was defined by a new NFS positivity or an increased value of a-N titre. Results: Overall, 201 LT-recipients have been infected by SARS-CoV-2 (62% males, median age=61yr, 50% viral-etiology, 35% with HCC, all received a CNI-based regimen, plus MMF=63%). Most of infections were diagnosed by NFS (72%);mild flu-like symptoms were observed in 59% of our LT recipients;72% of them remained untreated, while 28% received antivirals (11%) or monoclonal antibodies (17%). Fifteen LT recipients were hospitalized, 6 of them for interstitial pneumonia and 2 (both with previous lung diseases) died for COVID-19. Conclusions: A mild or asymptomatic infection occurred frequently in our LT recipients with a less severe outcome than the past waves. A possible explanation could be the high prevalence of vaccinated patients in our cohort. Interestingly, the overall prevalence of SARS Cov2 infection might be underestimated without a careful monitoring of SARS-CoV-2 serology against nucleocapsid.
ABSTRACT
Background: Vaccines provide effective protection against COVID-19. Nevertheless, concerns about their efficacy and safety have been reported.1-2 The term vaccine hesitancy refers to delay in the acceptance of vaccines (or total refusal) despite their availability.3 COVID-19 vaccination was strongly recommended for Liver Transplant (LT) recipients by the AASLD. The aim of our study was to assess COVID-19 vaccine hesitancy among LT patients, its reasons and possible determinants. Methods: Between January and February 2021, a web-based questionnaire was sent to LT patients followed at our liver transplant out-patient clinic in Milan, Italy. The questionnaire was adapted from a previous validated questionnaire.4 Patients were classified as willing, hesitant and refusing (totally opposing) to accept COVID-19 vaccination, and the reasons and possible factors influencing vaccine hesitancy were investigated. When the COVID-19 vaccines became available for LT candidates and recipients in Italy (March 2021), the entire cohort of LT recipients was contacted by phone and called for vaccination, and the rate of refusals recorded. Results: The web-based survey was sent to 583 patients, of whom 190 responded (response rate of 32.6%). Among the respondents, 157 (82.7%) were willing to be vaccinated against COVID-19, while 27 (14.2%) were hesitant and 6 (3.1%) did not answer this specific question. Among the hesitant, 3 were refusing, for a refusal rate of 1.5%. The reasons most frequently given by hesitant patients to justify their refusal (more than one could be indicated) was the fear of adverse events in 22/27 and concerns about the rapid development of COVID-19 vaccines in 17/27 (Figure). Thirteen hesitant patients (48.1%) answered that their COVID-19 vaccine hesitancy was influenced by being a transplant recipient. None of the possible determinants were significantly associated with vaccination hesitancy/refusal in multivariate analysis. Of the 667 patients followed at our Centre 628 were called by phone to be vaccinated and asked about their COVID-19 willingness and the 6.5% (41) of the patients refused the scheduled vaccination. Conclusion: Since it is crucial to achieve adequate vaccinations of LT patients, it is very important to identify the reasons influencing hesitancy so that appropriate patient-doctor communication can be established and specific vaccinations campaigns further implemented.