The Lancet Regional Health. Europe (Jun 2022)

Immunogenicity of BNT162b2 vaccine booster against SARS-CoV-2 Delta and Omicron variants in nursing home residents: A prospective observational study in older adults aged from 68 to 98 years

  • Enagnon Kazali Alidjinou,
  • Julie Demaret,
  • Bénédicte Corroyer-Simovic,
  • Julien Labreuche,
  • Anne Goffard,
  • Jacques Trauet,
  • Daniela Lupau,
  • Sophie Miczek,
  • Fanny Vuotto,
  • Arnaud Dendooven,
  • Dominique Huvent-Grelle,
  • Juliette Podvin,
  • Daniel Dreuil,
  • Karine Faure,
  • Dominique Deplanque,
  • Laurence Bocket,
  • Alain Duhamel,
  • Annie Sobaszek,
  • Didier Hober,
  • Michael Hisbergues,
  • Francois Puisieux,
  • Brigitte Autran,
  • Yazdan Yazdanpanah,
  • Myriam Labalette,
  • Guillaume Lefèvre

Journal volume & issue
Vol. 17
p. 100385

Abstract

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Summary: Background: The present study aimed to evaluate the persistent immunogenicity offered by a third dose of BNT162b2 against Delta and Omicron variants, in nursing home (NH) residents. Methods: In this monocenter prospective observational study, anti-spike IgG levels, S1 domain reactive T cell counts, serum neutralizing antibody titers against Delta and Omicron variants were compared before and up to three months after the BNT162b2 booster dose, in NH residents without COVID-19 (COVID-19 naive) or with COVID-19 prior to initial vaccination (COVID-19 recovered). Findings: 106 NH residents (median [interquartile range] age: 86·5 [81;91] years) were included. The booster dose induced a high increase of anti-spike antibody levels in all subjects (p < 0.0001) and a mild transient increase of specific T cells. Before the booster dose, Delta neutralization was detected in 19% (n = 8/43) and 88% (n = 37/42) of COVID-19 naive and COVID-19 recovered subjects, respectively. Three months after the booster dose, all NH residents developed and maintained a higher Delta neutralization (p < 0·0001). Before the booster dose, Omicron neutralization was detected in 5% (n = 2/43) and 55% (n = 23/42) of COVID-19 naive and COVID-19 recovered subjects, respectively, and three months after, in 84% and 95%, respectively. Neutralizing titers to Omicron were lower than to Delta in both groups with a 35-fold reduction compared to Delta. Interpretation: The booster dose restores high neutralization titers against Delta in all NH residents, and at a lower level against Omicron in a large majority of participants. Future studies are warranted to assess if repeated BNT162b2 booster doses or new specific vaccines might be considered for protecting such fragile patients against Omicron and/or future SARS-CoV-2 variants. Funding: French government through the Programme Investissement d'Avenir (I-SITE ULNE/ANR-16-IDEX-0004 ULNE) and the Label of COVID-19 National Research Priority (National Steering Committee on Therapeutic Trials and Other COVID-19 Research, CAPNET).

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