Differences in Strength and Longevity of SARS-CoV-2-Specific Adaptive Immunity Between Convalescent and Vaccinated SOT Patients and Immunocompetent Individuals

L. Donadeu¹, S. Gomez¹, A. Fava'², E. Crespo¹, F. Moreso³, M. Lopez³, L. Lladó⁴, J. González⁴, I. Campos³, M. Muñoz³, J. Quintero³, J. Esperalba³, O. Bestard³

¹Vall d’Hebron Institut de Recerca (VHIR), Barcelona, Spain, ²Bellvitge University Hospital, L'Hospitalet de Llobregat. Barcelona, Spain, ³Vall d’Hebron University Hospital (HUVH), Barcelona, Spain, ⁴Bellvitge University Hospital, L'Hospitalet de Llobregat, Spain

Meeting: 2022 American Transplant Congress

Abstract number: 980

Keywords: COVID-19, Immunogenicity, Infection, Vaccination

Topic: Clinical Science » Infection Disease » 24 - All Infections (Excluding Kidney & Viral Hepatitis)

Session Information

Session Name: All Infections (Excluding Kidney & Viral Hepatitis) II

Session Type: Poster Abstract

Date: Sunday, June 5, 2022

Session Time: 7:00pm-8:00pm

Presentation Time: 7:00pm-8:00pm

Location: Hynes Halls C & D

*Purpose: Short-term adaptive immune memory has been reported among immunocompetent (IC) and convalescent Solid Organ Transplant (SOT) individuals following SARS-CoV-2 infection as well as after active vaccination. However, quality and longevity of anti-viral immune memory comparisons between natural and active immunization has not been thoroughly assessed among SOT.

*Methods: SARS-CoV-2-specific adaptive immune memory was assessed at different compartments (serological, memory B cells [mBC] and cytokine [Th1: IFN-γ, IL-2, IFN-γ/IL-2 and Th2: IL-21 and IL-5] producing T cells) by ELISA and FluoroSpot-based assays, respectively, in 41 convalescent patients with severe COVID-19 (22 SOT and 19 IC) and 39 vaccinated patients (19 SOT and 20 IC) with a mRNA-based vaccine) at different time-points post immunization (T1=21days after infection/1^st dose; T2=3months after infection/2^nd dose; T3=6months after infection/2^nd dose). Additionally, a group of convalescent mild (19 SOT and 19 IC) and asymptomatic patients (9 SOT and 10 IC) were also evaluated at T3.

*Results: Overall, statistically significant higher immune responses in all immune compartments were observed in convalescent patients than among those after vaccination. After vaccination, low seropositivity rates (5,88%) were observed among SOT after 1^st dose, whereas seroconversion was fully achieved in IC patients and SOT with severe COVID-19 (p<0.001). Similarly, while the presence of mBc after vaccination progressively increased over time, it was less pronounced and significantly delayed among SOT than convalescent patients in all time points (p<0.001 T1, T2 and T3). SARS-CoV-2-specific Th1 and Th2 frequencies were significantly higher among vaccinated IC patients than SOT, being these responses significantly lower than those observed in convalescent among SOTT and IC patients (p<0.001 T1, T2 and T3). At 6 months after vaccination, IgG titers, mBc frequencies and Th1/Th2 T-cell responses after two-dose vaccination in SOT mimicked those observed in convalescent SOT with an asymptomatic/mild clinical COVID-19 infection.

*Conclusions: The type of immunization against SARS-CoV-2, either natural or active after vaccination, clearly differentiates the quality and length of adaptive immune memory, with a clear weaker immune response observed among SOT.

To cite this abstract in AMA style:

Donadeu L, Gomez S, Fava' A, Crespo E, Moreso F, Lopez M, Lladó L, González J, Campos I, Muñoz M, Quintero J, Esperalba J, Bestard O. Differences in Strength and Longevity of SARS-CoV-2-Specific Adaptive Immunity Between Convalescent and Vaccinated SOT Patients and Immunocompetent Individuals [abstract]. Am J Transplant. 2022; 22 (suppl 3). https://atcmeetingabstracts.com/abstract/differences-in-strength-and-longevity-of-sars-cov-2-specific-adaptive-immunity-between-convalescent-and-vaccinated-sot-patients-and-immunocompetent-individuals/. Accessed May 30, 2025.

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