B and T cell immune responses elicited by the BNT162b2 (Pfizer–BioNTech) COVID-19 vaccine in nursing home residents

  1. Ignacio Torres
  2. Eliseo Albert
  3. Estela Giménez
  4. María Jesús Alcaraz
  5. Pilar Botija
  6. Paula Amat
  7. María José Remigia
  8. María José Beltrán
  9. Celia Rodado
  10. Dixie Huntley
  11. Beatriz Olea
  12. David Navarro

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Abstract

Objectives

The immunogenicity of the BNT162b2 COVID-19 vaccine is understudied in elderly people with comorbidities. We assessed SARS-CoV-2-S-targeted antibody and T cell responses following full vaccination in nursing home residents (NHR).

Methods

We recruited 60 NHR (44 female; median age, 87.5 years), of whom 10 had previously had COVID-19, and 18 healthy controls (15 female; median age, 48.5 years). Pre- and post-vaccination blood specimens were available for quantitation of total antibodies binding RBD and enumeration of SARS-CoV-2-S-reactive IFN-γ CD4 + and CD8 + T cells by flow cytometry.

Results

The seroconversion rate in presumably SARS-CoV-2 naïve NHR (95.3%), either with or without comorbidities, was similar to controls (94.4%). A robust booster effect was documented in NHR with prior COVID-19. Plasma antibody levels were higher in convalescent NHR than in individuals across the other two groups. A large percentage of NHR had SARS-CoV-2 S-reactive IFN-γ CD8 + and/or CD4 + T cells at baseline, in contrast to healthy controls. Either CD8 + and/or CD4 + T-cell responses were documented in all control subjects after vaccination. Contrariwise, the percentage of NHR exhibiting detectable SARS-CoV-2 IFN-γ CD8 + or CD4 + T-cell responses (or both), irrespective of their baseline SARS-CoV-2 infection status, dropped consistently after vaccination. Overall, SARS-CoV-2 IFN-γ CD8 + and CD4 + T-cell responses in NHR decreased in post-vaccination specimens.

Conclusion

The BNT162b2 COVID-19 vaccine elicits robust SARS-CoV-2-S antibody responses in NHR. Nevertheless, the frequency and magnitude of detectable SARS-CoV-2 IFN-γ T-cell responses after vaccination was lower in NHR compared to controls.

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  1. ScreenIT

    SciScore for 10.1101/2021.04.19.21255723: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    EthicsConsent: Informed consent was obtained from participants.
    IRB: The study was approved by the Hospital Clínico Universitario INCLIVA Research Ethics Committee (February, 2021)
    Sex as a biological variableParticipants and study design: We enrolled a total of 60 subjects (44 female) onto the study, randomly selected from two NH affiliated to the Clínico-Malvarrosa Health Department, Valencia (Spain), which together provide care for 226 residents.
    RandomizationParticipants and study design: We enrolled a total of 60 subjects (44 female) onto the study, randomly selected from two NH affiliated to the Clínico-Malvarrosa Health Department, Valencia (Spain), which together provide care for 226 residents.
    Blindingnot detected.
    Power Analysisnot detected.

    Table 2: Resources

    No key resources detected.

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    The current study has several limitations that must be underlined. Firstly, the number of participants was relatively limited; second, the possibility that NHR displayed SARS-CoV-2-S-reactive T cells with functional specificities other than IFN-γ production was not explored. Additionally, a whole-blood flow cytometry assay was used to assess T-cell immunity: it is uncertain whether employing isolated peripheral blood mononuclear cells instead would increase sensitivity. Finally, no attempt was made to differentiate between truly SARS-CoV-2-specific and cross-reactive T cells, which can be accomplished according to recent reports, although this need further validation [20,21]. In summary, we were able to document robust SARS-CoV-2-S antibody responses equivalent to those of healthy controls in NHR following complete vaccination, irrespective of SARS-CoV-2 infection status and presence or absence of comorbidities. Nevertheless, our data point to differential vaccine effectivity between NHR and controls in terms of eliciting SARS-CoV-2 IFN-γ T-cell responses. In this context, the potential detrimental effect of pre-existing bona fide or cross-reactive SARS-CoV-2 immunity seen in NHR merits further investigation.

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    About SciScore

    SciScore is an automated tool that is designed to assist expert reviewers by finding and presenting formulaic information scattered throughout a paper in a standard, easy to digest format. SciScore checks for the presence and correctness of RRIDs (research resource identifiers), and for rigor criteria such as sex and investigator blinding. For details on the theoretical underpinning of rigor criteria and the tools shown here, including references cited, please follow this link.

  2. Version published to 10.1101/2021.04.19.21255723 on medRxiv