Early Omicron infection is associated with increased reinfection risk in older adults in long-term care and retirement facilities

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dc.contributor.author

Breznik, Jessica A.

Zhang, Ali

Ang, Jann

Stacey, Hannah D.

Bhakta, Hina

Clare, Rumi

Liu, Li-Min

Kennedy, Allison

Hagerman, Megan

Kajaks, Tara

Miller, Matthew S.

Nazy, Ishac

Bramson, Jonathan L.

Costa, Andrew P.

Bowdish, Dawn M. E.

Rahim, Ahmad

dc.date.accessioned

2025-01-29T15:48:12Z

dc.date.available

2025-01-29T15:48:12Z

dc.date.issued

2023-09

dc.description.abstract - en

<p>Background<br> Older adults are at increased risk of SARS-CoV-2 Omicron infection and severe disease, especially those in congregate living settings, despite high SARS-CoV-2 vaccine coverage. It is unclear whether hybrid immunity (combined vaccination and infection) after one Omicron infection provides increased protection against subsequent Omicron reinfection in older adults.</p> <p>Methods<br> Incidence of SARS-CoV-2 Omicron infection was examined in 750 vaccinated residents of long-term care and retirement homes in the observational cohort COVID in Long-Term Care Study in Ontario, Canada, within a 75-day period (July to September 2022). Risk of infection was assessed by Cox proportional hazards regression. Serum anti-spike and anti-RBD SARS-CoV-2 IgG and IgA antibodies, microneutralization titres, and spike-specific T cell memory responses, were examined in a subset of 318 residents within the preceding three months.</p> <p>Findings<br> 133 of 750 participants (17.7%) had a PCR-confirmed Omicron infection during the observation period. Increased infection risk was associated with prior Omicron infection (at 9–29 days: 47.67 [23.73–95.76]), and this was not attributed to days since fourth vaccination (1.00 [1.00–1.01]) or residence outbreaks (>6 compared to ≤6: 0.95 [0.37–2.41]). Instead, reinfected participants had lower serum neutralizing antibodies to ancestral and Omicron BA.1 SARS-CoV-2, and lower anti-RBD IgG and IgA antibodies, after their initial Omicron infection.</p> <p>Interpretation<br> Counterintuitively, SARS-CoV-2 Omicron infection was associated with increased risk of Omicron reinfection in residents of long-term care and retirement homes. Less robust humoral hybrid immune responses in older adults may contribute to risk of Omicron reinfection.</p>

dc.description.sponsorship

COVID-19 Immunity Task Force of the Public Health Agency of Canada.

dc.identifier.doi

https://doi.org/10.1016/j.eclinm.2023.102148

dc.identifier.issn

2589-5370

dc.identifier.pubmedID

37753447

dc.identifier.uri

https://open-science.canada.ca/handle/123456789/3375

dc.language.iso

en

dc.publisher - en

Elsevier Ltd

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.openaccesslevel - en

Gold

dc.rights.openaccesslevel - fr

Or

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

Seniors

dc.subject - fr

Santé

Maladie à coronavirus

Aîné

dc.subject.en - en

Health

Coronavirus diseases

Seniors

dc.subject.fr - fr

Santé

Maladie à coronavirus

Aîné

dc.title - en

Early Omicron infection is associated with increased reinfection risk in older adults in long-term care and retirement facilities

dc.type - en

Article

dc.type - fr

Article

local.acceptedmanuscript.articlenum

102148

local.article.journaltitle - en

eClinicalMedicine

local.article.journalvolume

63

local.pagination

1-15

local.peerreview - en

Yes

local.peerreview - fr

Oui

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