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RBD-IgG levels correlate with protection in Residents Facing SARS-CoV-2 B.1.1.7 Outbreaks
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  • Hubert Blain,
  • Edouard Tuaillon,
  • Lucie Gamon,
  • Amandine Pisoni,
  • Stephanie Miot,
  • Valentin Delpui,
  • Nejm Si-Mohamed,
  • Clémence Niel,
  • Yves Rolland,
  • Brigitte Montes,
  • Soraya Groc,
  • Sophia Rafasse,
  • Anne-Marie Dupuy,
  • Nathalie Gros,
  • Delphine Muriaux,
  • Marie-Christine Picot,
  • Jean Bousquet
Hubert Blain
Montpellier Universite d'Excellence
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Edouard Tuaillon
Montpellier Universite d'Excellence
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Lucie Gamon
Montpellier Universite d'Excellence
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Amandine Pisoni
Montpellier Universite d'Excellence
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Stephanie Miot
Montpellier Universite d'Excellence
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Valentin Delpui
Montpellier Universite d'Excellence
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Nejm Si-Mohamed
Montpellier Universite d'Excellence
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Clémence Niel
Montpellier Universite d'Excellence
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Yves Rolland
Centre Hospitalier Universitaire de Toulouse
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Brigitte Montes
Montpellier Universite d'Excellence
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Soraya Groc
Montpellier Universite d'Excellence
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Sophia Rafasse
Montpellier Universite d'Excellence
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Anne-Marie Dupuy
Montpellier Universite d'Excellence
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Nathalie Gros
Montpellier Universite d'Excellence
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Delphine Muriaux
Montpellier Universite d'Excellence
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Marie-Christine Picot
Montpellier Universite d'Excellence
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Jean Bousquet
Charite Universitatsmedizin Berlin
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Abstract

Background Limited information exists on nursing home (NH) residents regarding BNT162b2/Pfizer vaccine efficacy in preventing SARS-CoV-2 and severe Covid-19, and its association with post-vaccine humoral response. Methods 396 residents from seven NHs suffering a SARS-CoV-2 B.1.1.7 (VOC-α) outbreak at least 14 days after a vaccine campaign were repeatedly tested using SARS-CoV-2 real-time reverse-transcriptase polymerase chain reaction on nasopharyngeal swab test (RT-PCR). SARS-CoV-2 Receptor-Binding Domain (RBD) of the S1 subunit (RBD-IgG) was measured in all residents. Nucleocapsid antigenemia (N-Ag) was measured in RT-PCR-positive residents, and serum neutralizing antibodies in vaccinated residents from one NH. Results The incidence of positive RT-PCR was lower in residents vaccinated by two doses (22.7%) vs one dose (32.3%) or non-vaccinated residents (43.7%)(p<0.01). Covid-19-induced deaths were observed in 10.4% of the non-vaccinated residents, in 6.4% of those who had received one dose, and in 0.9% with two doses (p=0.0007). Severe symptoms were more common in infected non-vaccinated (21.0%) vs vaccinated residents (47.6%, p=0.002). Higher levels of RBD-IgG (n=325) were associated with a lower SARS-CoV-2 incidence. No in vitro serum neutralization activity was found for RBD-IgG levels below 1,050 AU/mL. RBD-IgG levels were inversely associated with N-Ag levels, found as a risk factor of severe Covid-19. Conclusions Two BNT162b2/Pfizer doses are associated with a 48% reduction of SARS-CoV-2 incidence and a 91.3% reduction of death risk in residents from NHs facing a VOC-α outbreak. BNT162b2/Pfizer efficacy was partly predicted by post-vaccine RBD-IgG levels.

Peer review status:ACCEPTED

11 Sep 2021Submitted to Allergy
11 Sep 2021Submission Checks Completed
11 Sep 2021Assigned to Editor
12 Sep 2021Reviewer(s) Assigned
24 Sep 2021Review(s) Completed, Editorial Evaluation Pending
24 Sep 2021Editorial Decision: Revise Minor
29 Sep 20211st Revision Received
29 Sep 2021Submission Checks Completed
29 Sep 2021Assigned to Editor
01 Oct 2021Editorial Decision: Accept