Kinetics of cellular and humoral responses to third BNT162B2 COVID-19 vaccine over six months in heart transplant recipients – implications for the omicron variant

Yael Peled, Arnon Afek, Yitshak Kreiss, Galia Rahav, Ital Nemet, Limor Kliker, Victoria Indenbaum, Eilon Ram, Jacob Lavee, Amit Segev, Shlomi Matezki, Leonid Sternik, Ehud Raanani, Yaniv Lustig, Jignesh K. Patel, Michal Mandelboim

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


Background: The durability of the immune response following the 3-dose BNT162b2 vaccination is unknown. The complexity of the situation is enhanced by the threat that highly transmissible variants may further accelerate the decline in the protection afforded by mRNA vaccines. Methods: One hundred and three 3-dose-vaccinated heart transplant recipients were longitudinally assessed for the kinetics of variant-specific neutralization (Cohort 1, n = 60) and SARS-CoV-2-specific-T-cell response (Cohort 2, n = 54) over 6 months. Neutralization and T-cell responses were compared between paired samples at 2 time points, using the Kruskal-Wallis test followed by Dunn's multiple comparison test for continuous variables and McNemar's test for dichotomous variables. The Bonferroni method of p values adjustment for multiple comparison was applied. Results: The third dose induced high neutralization of the wild-type virus and delta variant (geometric mean titer [GMT], 137.2 [95% CI, 84.8-221.9] and 80.6, [95% CI, 49.3-132.0], respectively), and to a lesser degree of the omicron variant (GMT, 10.3 [95% CI, 5.9-17.9]). At 6 months, serum neutralizing activity declined but was still high for the wild-type virus and for the delta variant (GMTs 38.1 [95% CI, 21.2-69.4], p = 0.011; and 28.9 [95% CI, 16.6-52.3], p = 0.022, respectively), but not for the omicron variant (GMT 5.9 [95% CI, 3.4-9.8], p = 0.463). The percentages of neutralizing sera against the wild-type virus, delta and omicron variants increased from 70%, 65%, and 38%, before the third dose, to 93% (p < 0.001), 88% (p < 0.001), and 48% (p = 0.021) at 3 weeks after, respectively; and remained high through the 6 months for the wild-type (80%, p = 0.06) and delta (77%, p = 0.102). The third dose induced the development of a sustained SARS-CoV-2-specific-T-cell population, which persisted through 6 months. Conclusions: The third BNT162b2 dose elicited a durable SARS-CoV-2-specific T-cell response and induced effective and durable neutralization of the wild-type virus and the delta variant, and to a lesser degree of the omicron variant.

Original languageEnglish
Pages (from-to)1417-1425
Number of pages9
JournalJournal of Heart and Lung Transplantation
Issue number10
StatePublished - Oct 2022
Externally publishedYes

Bibliographical note

Funding Information:
The authors gratefully acknowledge the invaluable contribution of Ms. Hana Algazi-Patal, the coordinator of heart transplants at the Sheba Medical Center, Ms. Sarit Skiano, Ms. Michal Kelishek, Ms. Merav Moreno, Ms. Tal Aharon Ms. Eitana Mor, Ms. Ravid Amitai and Mr. Aharon Greitzer, of the Heart Transplant Unit, Sheba Medical Center, for organizing the vaccination effort for our cohort.

Publisher Copyright:
© 2022 International Society for Heart and Lung Transplantation


  • BNT162b2 vaccine
  • SARS-CoV-2-specificT-cell
  • heart transplantation
  • neutralization
  • omicron


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