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Antibody response after one and two doses of the BNT162b2 vaccine in nursing home residents: The CONsort-19 study
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  • Jean Bousquet,
  • Hubert Blain,
  • Edouard Tuaillon,
  • Lucie Gamon,
  • Amandine Pisoni,
  • Stephanie Miot,
  • Yves Rolland,
  • Marie-Christine Picot
Jean Bousquet
Université Versailles, St-Quentin-en-Yvelines
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Hubert Blain
CHU Montpellier
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Edouard Tuaillon
CHU Montpellier
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Lucie Gamon
CHU Montpellier
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Amandine Pisoni
CHU Montpellier
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Stephanie Miot
CHU Montpellier
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Yves Rolland
CHU
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Marie-Christine Picot
CHU Montpellier
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Abstract

Methods: Twenty-two French nursing homes were included. COVID-19 had been diagnosed with real-time reverse-transcriptase polymerase chain reaction (RT-PCR) for SARS-CoV-2. Blood S-protein IgG and nucleocapsid (N) IgG protein (N-protein IgG) were measured 21-24 days after the first jab (1,004 residents) and 6 weeks after the second (820 residents). Results: Among the 735 residents without prior COVID-19, 41.7% remained seronegative for S-protein IgG after the first jab vs 2.1% of the 270 residents with a previous positive RT-PCR (p<0.001). After the second jab, only 3% of the 586 residents without prior COVID-19 remained seronegative. However, 26.5% of them had low S-protein IgG levels (50-1050 UA/mL) vs 6.4% of the 222 residents with prior COVID-19. Residents with old infection (first wave), or seropositive for N-protein IgG at the time of vaccination, had the highest S-protein IgG levels. Residents with a prior COVID-19 infection had higher S-protein IgG levels after one dose than those without two jabs. Interpretation: A single vaccine jab is sufficient to reach immunity in residents with prior COVID-19. Most residents without prior COVID-19 are seropositive for S-protein IgG after the second jab, but around 30% have low levels of S-protein IgG. Whether residents with no or low post-vaccine immunity are at higher risk of symptomatic COVID-19 requires further analysis.

Peer review status:ACCEPTED

07 May 2021Submitted to Allergy
07 May 2021Submission Checks Completed
07 May 2021Assigned to Editor
07 May 2021Reviewer(s) Assigned
16 May 2021Review(s) Completed, Editorial Evaluation Pending
17 May 2021Editorial Decision: Revise Minor
31 May 20211st Revision Received
01 Jun 2021Submission Checks Completed
01 Jun 2021Assigned to Editor
01 Jun 2021Reviewer(s) Assigned
03 Jun 2021Review(s) Completed, Editorial Evaluation Pending
03 Jun 2021Editorial Decision: Accept