Effectiveness and Duration of Protection of a Fourth Dose of Coronavirus Disease 2019 Messenger RNA Vaccine Among Long-term Care Residents in Ontario, Canada

Ramandip Grewal; Lena Nguyen; Sarah A Buchan; Sarah E Wilson; Andrew P Costa; Jeffrey C Kwong

doi:10.1093/infdis/jiac468

Effectiveness and Duration of Protection of a Fourth Dose of Coronavirus Disease 2019 Messenger RNA Vaccine Among Long-term Care Residents in Ontario, Canada

J Infect Dis. 2023 Apr 18;227(8):977-980. doi: 10.1093/infdis/jiac468.

Authors

Ramandip Grewal¹, Lena Nguyen², Sarah A Buchan^{1

2

3

4}, Sarah E Wilson^{1

2

3

4}, Andrew P Costa^{5

6

7}, Jeffrey C Kwong^{1

2

3

4

8

9}

Affiliations

¹ Public Health Ontario, Toronto, Ontario, Canada.
² ICES, Toronto, Ontario, Canada.
³ Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada.
⁴ Centre for Vaccine Preventable Diseases, University of Toronto, Toronto, Ontario, Canada.
⁵ Department of Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada.
⁶ Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Ontario, Canada.
⁷ Centre for Integrated Care, St Joseph's Health System, Hamilton, Ontario, Canada.
⁸ Department of Family and Community Medicine, University of Toronto, Toronto, Ontario, Canada.
⁹ University Health Network, Toronto, Ontario, Canada.

PMID: 36461711
DOI: 10.1093/infdis/jiac468

Abstract

We estimated the effectiveness of a fourth dose of messenger RNA coronavirus disease 2019 vaccine against Omicron infections and severe outcomes over time among long-term care residents in Ontario, Canada. Fourth doses provide additional protection against Omicron-related outcomes, but the protection wanes over time, with more waning seen against infection than severe outcomes.

Keywords: COVID-19; duration of protection; fourth doses; long-term care residents; marginal effectiveness; vaccine effectiveness.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

COVID-19 Vaccines*
COVID-19* / prevention & control
Humans
Long-Term Care
Ontario / epidemiology
RNA, Messenger
mRNA Vaccines

Substances

COVID-19 Vaccines
RNA, Messenger
mRNA Vaccines