Weak humoral immune reactivity among residents of long-term care facilities following one dose of the BNT162b2 mRNA COVID-19 vaccine

Brockman, Mark A.; Mwimanzi, Francis; Sang, Yurou; Ng, Kurtis; Agafitei, Olga; Ennis, Siobhan; Lapointe, Hope; Young, Landon; Umviligihozo, Gisele; Burns, Laura; Brumme, Chanson; Leung, Victor; Montaner, Julio S.G.; Holmes, Daniel; DeMarco, Mari; Simons, Janet; Niikura, Masa; Pantophlet, Ralph; Romney, Marc G.; Brumme, Zabrina L.

Weak humoral immune reactivity among residents of long-term care facilities following one dose of the BNT162b2 mRNA COVID-19 vaccine

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dc.contributor.author: Brockman, Mark A.; Mwimanzi, Francis; Sang, Yurou; Ng, Kurtis; Agafitei, Olga; Ennis, Siobhan; Lapointe, Hope; Young, Landon; Umviligihozo, Gisele; Burns, Laura; Brumme, Chanson; Leung, Victor; Montaner, Julio S.G.; Holmes, Daniel; DeMarco, Mari; Simons, Janet; Niikura, Masa; Pantophlet, Ralph; Romney, Marc G.; Brumme, Zabrina L.
dc.date.accessioned: 2025-01-28T21:26:43Z
dc.date.available: 2025-01-28T21:26:43Z
dc.date.issued: 2021-03-24
dc.description.abstract - en: Background Several Canadian provinces are extending the interval between COVID-19 vaccine doses to increase population vaccine coverage more rapidly. However, immunogenicity of these vaccines after one dose is incompletely characterized, particularly among the elderly, who are at greatest risk of severe COVID-19. Methods We assessed SARS-CoV-2 humoral responses pre-vaccine and one month following the first dose of BNT162b2 mRNA vaccine, in 12 COVID-19 seronegative residents of long-term care facilities (median age, 82 years), 18 seronegative healthcare workers (HCW; median age, 36 years) and 4 convalescent HCW. Total antibody responses to SARS-CoV-2 nucleocapsid (N) and spike protein receptor binding domain (S/RBD) were assessed using commercial immunoassays. We quantified IgG and IgM responses to S/RBD and determined the ability of antibodies to block S/RBD binding to ACE2 receptor using ELISA. Neutralizing antibody activity was also assessed using pseudovirus and live SARS-CoV-2. Results After one vaccine dose, binding antibodies against S/RBD were ∼4-fold lower in residents compared to HCW (p<0.001). Inhibition of ACE2 binding was 3-fold lower in residents compared to HCW (p=0.01) and pseudovirus neutralizing activity was 2-fold lower (p=0.003).While six (33%) seronegative HCW neutralized live SARS-CoV-2, only one (8%) resident did (p=0.19). In contrast, convalescent HCW displayed 7- to 20-fold higher levels of binding antibodies and substantial ability to neutralize live virus after one dose. Interpretation Extending the interval between COVID-19 vaccine doses may pose a risk to the elderly due to lower vaccine immunogenicity in this group. We recommend that second doses not be delayed in elderly individuals.
dc.description.sponsorship: This work was supported by the Public Health Agency of Canada through a COVID-19 Immunology Task Force COVID-19 "Hot Spots" Award (2021-HQ-000120 to MAB, ZLB, MGR), the National Institute of Allergy and Infectious Diseases of the National Institutes of Health (R01AI134229 to RP), and the Canada Foundation for Innovation through Exceptional Opportunities Fund COVID-19 awards (project #40947 to MAB, MN, ZLB; project #41067 to RP). MAB holds a Canada Research Chair, Tier 2, in viral pathogenesis and immunity. ZLB holds a Scholar Award from the Michael Smith Foundation for Health Research.
dc.identifier.doi: https://doi.org/10.1101/2021.03.17.21253773
dc.identifier.uri: https://open-science.canada.ca/handle/123456789/3373
dc.language.iso: en
dc.publisher - en: medRxiv
dc.publisher - fr: medRxiv
dc.rights - en: Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)
dc.rights - fr: Creative Commons Attribution - Pas d'utilisation commerciale - Pas de modification 4.0 International (CC BY-NC-ND 4.0)
dc.rights.uri - en: https://creativecommons.org/licenses/by-nc-nd/4.0/
dc.rights.uri - fr: https://creativecommons.org/licenses/by-nc-nd/4.0/deed.fr
dc.subject - en: Health; Coronavirus diseases; Immunization
dc.subject - fr: Santé; Maladie à coronavirus; Immunisation
dc.subject.en - en: Health; Coronavirus diseases; Immunization
dc.subject.fr - fr: Santé; Maladie à coronavirus; Immunisation
dc.title - en: Weak humoral immune reactivity among residents of long-term care facilities following one dose of the BNT162b2 mRNA COVID-19 vaccine
dc.type - en: Submitted manuscript
dc.type - fr: Manuscrit soumis
local.pagination: 1-10
local.peerreview - en: No
local.peerreview - fr: Non
local.requestdoi - en: No
local.requestdoi - fr: No

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