Humoral and cellular immune responses to Pfizer-BioNTech BNT162b2 SARS-CoV-2 vaccine in adolescents with liver transplantation: Single center experience

Abstract

BackgroundImmune responses to vaccines against severe acute respiratory syndrome (SARS)-coronavirus (CoV)-2 are variable. In the absence of disease, youngsters are expected to better react to vaccines than adults. Nevertheless, chronic immunosuppression in transplant recipients may impair their capability to generate protection. We aim to explore immune responses after BNT162b2 SARS-CoV-2 vaccination in our cohort of young liver-transplanted patients.MethodsA prospective study of adolescent liver-transplanted patients (n=33) in the long-term follow-up was performed. Immune responses after receiving Pfizer-BioNTech BNT162b2 vaccine were analyzed at two time-points: baseline and 30 days after the second dose. Humoral responses were measured by fluoroenzyme-immunoassay and T-cell responses by interferon-γ-release assay. Post-vaccine coronavirus disease (COVID-19) events were recorded by a survey.ResultsPre-vaccine SARS-CoV-2-specific antibodies were undetectable in 27/32 (84.4%), negative/indeterminate in 3/32 (9.4%) and positive in 2/32 (6.3%) patients. Cellular responses at baseline were negative in 12/18 (66.6%), positive in 3/18 (16.6%) and indeterminate in 3/18 (16.6%) recipients. None of the baseline positives recalled any symptoms. Post-vaccine antibodies were detected in all patients and 92.6% showed levels >816 BAU/mL. Twenty (71.4%) recipients had positive T-cell responses. Regarding post-vaccine SARS-Cov-2 infection, 10 (30.3%) patients reported COVID-19 without hospitalization and 21 (63.6%) did not notify any infection. Negative and positive cell-response groups after vaccination showed statistically significant differences regarding COVID-19 cases (62.5% vs 22.2%, respectively; p=0.046).ConclusionsAdolescents and young adults with liver transplantation responded to SARS-Cov-2 vaccine, generating both humoral and cellular responses. Recipients developing cellular responses after vaccination had a lower incidence of COVID-19.

Ursodeoxycholic acid does not affect the clinical outcome of SARS‐CoV‐2 infection: A retrospective study of propensity score‐matched cohorts

“…Subjects with chronic liver disease are known to have a good seroconversion rate after vaccination for SARS‐CoV2 while the liver transplant recipients have a reduced response and need multiple close booster doses 43 . The number of administered doses and the time elapsed between the last administered dose and the time of infection may have influenced our results, but vaccination response to the first dose may also have significantly influenced the data observed in the SECURE‐liver registry, as the response to vaccination in transplant recipients can be highly variable 44,45 …”

Safety and Efficacy of a Third Dose of the BNT162b2 Vaccine in Liver-Transplanted and Healthy Adolescents

“…Although the BNT162b2 vaccine has been approved for use in children over the age of 12 since May 2021, data on its efficacy and safety in immunocompromised hosts, including liver‐transplanted (LT) adolescents, is scarce. Only one study from our group (3) and one from Spain (4) demonstrated that LT adolescents had a good immunogenic response after a 2‐dose regimen (30 µg) of the BNT162b2 vaccine. However, during the era of virus mutation from the Delta variant (B1.617.2) to the Omicron variant (B1.1.529), none of the LT adolescents and only one‐third of healthy adolescents had positive surrogate virus‐neutralizing antibodies (NAs) (>30%) to the Omicron variant (B1.1.529) (3).…”