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Immunogenicity of a BNT162b2 Vaccine Booster Against SARS-CoV-2 Delta and Omicron Variants in Older People
19 Pages Posted: 17 Feb 2022
More...Abstract
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 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 3 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. Repeated BNT162b2 booster doses or new specific vaccines might be considered for protecting such fragile patients.
Trial Registration Details: The study was registered in ClinicalTrials.gov, with the identifier NCT04760704.
Funding Information: 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).
Declaration of Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
Ethics Approval Statement: This study was performed in accordance with the Declaration of Helsinki principles for ethical research. The study was approved by the Ile-De-France V (ID-CRB 2021-A00119-32) ethics committee. All participants (and/or their legal representative if required) received detailed information and signed a consent form before participating in the study.
Keywords: BNT162b2 vaccine, boost, SARS-CoV-2, Delta, Omicron, older people, immunogenicity
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