Immunogenicity and safety of a third dose of anti‐SARS‐CoV‐2 BNT16b2 vaccine in liver transplant recipients

Abstract

Background & Aims A strategy to improve the low rate of anti‐SARS‐CoV‐2 mRNA vaccine‐induced immunogenicity in liver transplant recipients (LTs) is urgently needed. Methods We analyzed the rate of positive (≥0.8 U/ml) anti‐SARS‐CoV‐2 receptor domain binding protein (RBD) antibody response two months after a third dose of the BNT16b2 vaccine in 107 LTs who completed the second vaccine dose seven months earlier. Results A positive anti‐SARS‐CoV‐2‐s‐RBD antibody response after the third vaccine dose was detected in 98 (91.6%) LTs compared to 82 (76.6%) after the second vaccine dose (p=0.003). The median of anti‐SARS‐CoV‐2 RBD antibody titers increased from 22.9 U/ml six months after the second to 3500 U/ml two months after the third vaccine dose (p<0.001). Fourteen (14.3%) responder patients presented antibody titers <100 U/ml, 57 (58.2%) between 100 and 9999 U/ml and 27 (27.6%) ≥10000 U/ml. Seropositivity after the second dose was maintained after the third dose. Independent predictors of antibody response failure after the third vaccine dose were taking a higher daily dose of mycophenolate mofetil (MMF, p<0.001) and had a lower (<60 ml/min/1.73m 2 ) estimated glomerular filtration rate (p=0.007). Nine (9.1%) LTs experienced symptomatic SARS‐CoV‐2 infection after the third vaccine dose. Median antibody titers were not statistically different between infected and not infected LTs (1325 vs 3515 U/ml, p=0.678). Conclusions The third dose of the BNT16b2 vaccine increased the number of LTs who developed a positive anti‐SARS‐CoV‐2 s‐RBD antibody response. A proportion of patients remained unresponsive, mainly for modifiable factors, such the use of MMF or multiple immunosuppressants.

Impact of HLA divergence on humoral response to SARS-CoV-2 and HBV vaccines in the liver transplantation setting

“…Independent of the effect of the DQB1 HED, our study confirms the role of factors previously associated with SARS-Cov2 vaccine response in liver transplant recipients, such as age, time since transplant, mycophenolate treatment 27 , and identifies others not described, such as the hemoglobin level. Data on HBV vaccine response in liver transplant candidates are scarce in the literature.…”

Third dose of mRNA COVID‐19 vaccine and response: Correspondence

“…The current study has the potential to provide evidence on vaccination response among liver transplant recipients. The findings of Toniutto et al 1 confirm the utility of the third dose. This is consistent with the findings of a recent pathophysiological investigation on the effect of the third dosage of COVID‐19 vaccination.…”

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We would like to correspond on the publication 'Immunogenicity and safety of a third dose of anti-SARS-CoV-2 BNT16b2 vaccine in liver transplant recipients'. 1 The third dosage of the BNT16b2 vaccine boosted the number of liver transplant cases who acquired a positive anti-SARS-CoV-2s-RBD antibody response, according to Toniutto et al 1 We all believe that the vaccine is beneficial, and that liver transplant recipients may have a different immunological response to the immunisation than healthy people. The current study has the potential to provide evidence on vaccination response among liver transplant recipients.

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Vaccination against SARS‐CoV‐2 in liver transplant recipients: The game is still long and the outcome is uncertain

“…The game is still long and the outcome is uncertain Dear Editor, We thank Dr Sookaromdee et al for the positive comments on our paper. 1 We demonstrated that a positive anti-SARS-CoV-2-s-RBD antibody response after the third BNT16b2 vaccine dose was detected in more than 90% of liver transplant patients (LT), and more than 80% of them developed a median antibody titre >100 U/ml.…”