Limited durability of protection conferred by XBB.1.5 vaccines against omicron-associated severe outcomes among community-dwelling adults, Ontario, Canada

We estimated XBB.1.5 vaccine effectiveness (VE) against hospitalization/death among adults aged ≥50 years in Ontario, Canada, from September 2023 to June 2024. Compared with non-XBB.1.5 vaccinees, the initial protection at 0-3 months was 64 % (95 %CI, 57 %-69 %) during XBB-sublineage predominance. It was reduced to 57 % (95 %CI, 48 %-64 %) when JN/KP-sublineages became predominant, and quickly declined. No significant protection was observed >6 months post-vaccination. The VE estimates were lower when the last vaccine dose in the reference group was given more recently than 12 months, or was the omicron-containing bivalent vaccine. Short durability of protection poses unique challenges for COVID-19 vaccination.

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Publication Details

Journal
Vaccine
Published
2025-05-26
DOI
https://doi.org/10.1016/j.vaccine.2025.127300
Citations
1
Primary Topic
SARS-CoV-2 and COVID-19 Research
Type
article
Field-Weighted Citation Impact
1.40
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article

Limited durability of protection conferred by XBB.1.5 vaccines against omicron-associated severe outcomes among community-dwelling adults, Ontario, Canada

Kevin L. Schwartz, Kevin Antoine Brown, Sharifa Nasreen, Kumanan Wilson et al.
1 citations
Vaccine
SARS-CoV-2 and COVID-19 Research
1.40
article

Limited durability of protection conferred by XBB.1.5 vaccines against omicron-associated severe outcomes among community-dwelling adults, Ontario, Canada

Kevin L. Schwartz, Kevin Antoine Brown, Sharifa Nasreen, Kumanan Wilson, Peter C. Austin, Mina Tadrous, Ramandip Grewal, Jeffrey C. Kwong, Nelson Lee, Sarah A. Buchan, Sarah E Wilson, Lena Nguyen
article en
1 citations

Abstract

We estimated XBB.1.5 vaccine effectiveness (VE) against hospitalization/death among adults aged ≥50 years in Ontario, Canada, from September 2023 to June 2024. Compared with non-XBB.1.5 vaccinees, the initial protection at 0-3 months was 64 % (95 %CI, 57 %-69 %) during XBB-sublineage predominance. It was reduced to 57 % (95 %CI, 48 %-64 %) when JN/KP-sublineages became predominant, and quickly declined. No significant protection was observed >6 months post-vaccination. The VE estimates were lower when the last vaccine dose in the reference group was given more recently than 12 months, or was the omicron-containing bivalent vaccine. Short durability of protection poses unique challenges for COVID-19 vaccination.

VaccineVol. 60
State University of New York (US), Toronto Public Health (CA), University of Toronto (CA), Ottawa Hospital (CA), Women's College Hospital (CA), Public Health Ontario (CA), Bruyère (CA), Institute for Clinical Evaluative Sciences (CA)
Zero hunger
Openalex Percentile: Top 20%
SARS-CoV-2 and COVID-19 Research
1.40
DOIOpen Access PDFOpenAlex
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