Safety and Humoral and Cellular Immunogenicity of the BNT162b2 SARS-CoV-2 Vaccine in Liver-Transplanted Adolescents Compared to Healthy Adolescents

Abstract

Since BNT162b2 was approved to prevent COVID-19 in children, we aim to compare the safety and immunogenicity of the BNT162b2 vaccine in liver-transplanted (LT) and healthy adolescents. LT and healthy adolescents received two doses of 30 µg of BNT162b2. All were evaluated for total COVID-19 antibodies directed against the receptor-binding domain (RBD) and interferon-γ using the ELISpot at all time points; anti-nucleocapsid immunoglobulin was evaluated at week 8 and the surrogate virus-neutralizing antibody (sVN) to Omicron at day 0 and week 8. Adverse effects were recorded during days 0–7. In total, 16 LT and 27 healthy adolescents were enrolled (aged 14.78 ±1.70 years). After completion, all LT and healthy adolescents were positive for anti-RBD immunoglobulin, with geometric mean titers of 1511.37 (95% CI 720.22–3171.59) and 6311.90 (95% CI 4955.46–8039.64)) U/mL (p <0.001). All tested negative for anti-nucleocapsid immunoglobulin, indicating no COVID-19 infection after vaccination. However, the sVNs to Omicron were positive in only nine (33.33%) healthy adolescents and none of the LT adolescents. Interferon-γ-secreting cells were lower in LT adolescents than healthy adolescents. The LT adolescents had a lower immunogenic response to BNT162b2 than the healthy adolescents. Administrating two doses of BNT162b2 was safe, but was less effective against the Omicron variant.

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

“…We reported higher antibody response to BNT162b2 vaccine in young liver-transplanted recipients compared to adult cohorts, as observed by Sintusek et al (8). Similar to the observation by these authors, all participants in our study showed antibody response, compared to 73.3% reported by Qin et al (7) in solid-organ transplanted children.…”

“…Our findings suggest that adolescent with liver transplantation are able to mount robust immune responses to SARS-CoV-2 vaccination. As expected for younger cohorts, our patients showed higher percentages of immune responses when compared to older liver-transplanted recipients ( 6 – 8 ). The more information we have about the immune response against SARS-CoV-2 in immunosuppressed transplanted patients, the better we can establish the risk of developing disease following infection ( 19 ).…”

“…In our cohort, cellular responses were detectable in a lower percentage than humoral responses (71.4% vs 96.3%, respectively), as previously described ( 8 ). Differences may be explained because the techniques detecting both types of responses show distinctive sensitivity and specificity.…”

“…In a similar cohort of patients, Sintusek et al. ( 8 ) described lower T-cell response against the S protein in liver-transplanted adolescents than healthy controls, although the association of IFN-γ-secreting T cells with disease prevention and severity in infected participants will be part of further assessments. Nonetheless, robust T-cell activation likely contributes to a significant protection against hospitalization or death, as suggested by current observations ( 14 ).…”

“…On the other hand, it has been observed that pediatric solidorgan recipients show a higher percentage (73.3%) of antibody response to vaccines than adults (7). In a recent publication, Sintusek et al (8) studied the safety and immune response to BNT162b2 SARS-CoV-2 vaccine in a cohort of 16 liver-transplanted and 27 healthy adolescents. These authors concluded that the administration of two doses of this vaccine was safe, but less effective against the omicron variant in livertransplant recipients than healthy individuals, since they developed weaker cellular responses.…”