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Protection from Omicron Infection in Residents of Nursing and Retirement Homes in Ontario, Canada.
Breznik, Jessica A; Rahim, Ahmad; Kajaks, Tara; Hagerman, Megan; Bilaver, Lucas; Colwill, Karen; Dayam, Roaya M; Gingras, Anne-Claude; Verschoor, Chris P; McElhaney, Janet E; Bramson, Jonathan L; Bowdish, Dawn M E; Costa, Andrew P.
  • Breznik JA; McMaster Immunology Research Center, McMaster University, Hamilton, Ontario, Canada; Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada; Department of Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario,
  • Rahim A; Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Ontario, Canada.
  • Kajaks T; McMaster Institute for Research on Aging, McMaster University, Hamilton, Ontario, Canada; Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Ontario, Canada.
  • Hagerman M; McMaster Immunology Research Center, McMaster University, Hamilton, Ontario, Canada; Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada; Department of Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario,
  • Bilaver L; McMaster Immunology Research Center, McMaster University, Hamilton, Ontario, Canada; Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada; Department of Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario,
  • Colwill K; Lunenfeld-Tanenbaum Research Institute at Mount Sinai Hospital Sinai Health, Toronto, Ontario, Canada.
  • Dayam RM; Lunenfeld-Tanenbaum Research Institute at Mount Sinai Hospital Sinai Health, Toronto, Ontario, Canada.
  • Gingras AC; Lunenfeld-Tanenbaum Research Institute at Mount Sinai Hospital Sinai Health, Toronto, Ontario, Canada; Department of Molecular Genetics University of Toronto, Toronto, Ontario, Canada.
  • Verschoor CP; McMaster Institute for Research on Aging, McMaster University, Hamilton, Ontario, Canada; Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Ontario, Canada; Health Sciences North Research Institute, Sudbury, Ontario, Canada.
  • McElhaney JE; Health Sciences North Research Institute, Sudbury, Ontario, Canada; Posthumous.
  • Bramson JL; McMaster Immunology Research Center, McMaster University, Hamilton, Ontario, Canada; Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada; Department of Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario,
  • Bowdish DME; McMaster Immunology Research Center, McMaster University, Hamilton, Ontario, Canada; Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada; Department of Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario,
  • Costa AP; Department of Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada; McMaster Institute for Research on Aging, McMaster University, Hamilton, Ontario, Canada; Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Ontari
J Am Med Dir Assoc ; 24(5): 753-758, 2023 05.
Article in English | MEDLINE | ID: covidwho-2253001
ABSTRACT

OBJECTIVES:

To identify factors that contribute to protection from infection with the Omicron variant of SARS-CoV-2 in older adults in nursing and retirement homes.

DESIGN:

Longitudinal cohort study with retrospective analysis of infection risk. SETTING AND

PARTICIPANTS:

997 residents of nursing and retirement homes from Ontario, Canada, in the COVID in LTC study.

METHODS:

Residents with 3 messenger RNA (mRNA) dose vaccinations were included in the study. SARS-CoV-2 infection was determined by positive nasopharyngeal polymerase chain reaction test and/or circulating antinucleocapsid IgG antibodies. Cumulative probability of Omicron infection after recent COVID-19 was assessed by log-rank test of Kaplan-Meier curves. Cox regression was used to assess risk of Omicron infection by age, sex, mRNA vaccine combination, whether individuals received a fourth dose, as well as recent COVID-19.

RESULTS:

In total, 171 residents (17.2%) had a presumed Omicron variant SARS-CoV-2 infection between December 15, 2021 (local start of the first Omicron wave) and May 3, 2022. Risk of Omicron infection was not different by age [hazard ratio (95% confidence interval) 1.01 (0.99‒1.02)], or in women compared with men [0.97 (0.70‒1.34)], but infection risk decreased 47% with 3 vaccine doses of mRNA-1273 (Moderna) compared with BNT162b2 (Pfizer) [0.53 (0.31-0.90)], 81% with any fourth mRNA vaccine dose [0.19 (0.12‒0.30)], and 48% with SARS-CoV-2 infection in the 3 months prior to beginning of the Omicron wave [0.52, (0.27‒0.99)]. CONCLUSIONS AND IMPLICATIONS Vaccine type (ie, mRNA-1273/Spikevax vs BNT162b2/Cominarty), any fourth vaccine dose, and hybrid immunity from recent COVID-19, were protective against infection with the Omicron variant. These data emphasize the importance of vaccine type, and number of vaccine doses, in maintenance of protective immunity and reduction of risk of Omicron variant breakthrough infection. These findings promote continued public health efforts to support vaccination programs and monitor vaccine immunogenicity in older adults.
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Full text: Available Collection: International databases Database: MEDLINE Main subject: COVID-19 / BNT162 Vaccine Type of study: Cohort study / Observational study / Prognostic study Topics: Vaccines / Variants Limits: Aged / Female / Humans / Male Country/Region as subject: North America Language: English Journal: J Am Med Dir Assoc Journal subject: History of Medicine / Medicine Year: 2023 Document Type: Article

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Full text: Available Collection: International databases Database: MEDLINE Main subject: COVID-19 / BNT162 Vaccine Type of study: Cohort study / Observational study / Prognostic study Topics: Vaccines / Variants Limits: Aged / Female / Humans / Male Country/Region as subject: North America Language: English Journal: J Am Med Dir Assoc Journal subject: History of Medicine / Medicine Year: 2023 Document Type: Article