Triple COVID-19 jabs 61% effective against symptomatic Omicron, 95% against severe disease
Embargoed until:
Publicly released:
2022-09-23 01:00
Canadian and US scientists looked at data from 134,435 Canadians, and say being triple vaxxed against COVID-19 is 61% effective against symptomatic Omicron infection, and 95% effective against severe disease from Omicron. The researchers say two vaccine doses were 89% effective against symptomatic disease from the Delta variant, increasing to 97% after a third jab, but two doses were just 36% effective against symptomatic Omicron, rising to 61% after a third dose. The effectiveness of triple vaccines in preventing severe disease was 99% for Delta, and 95% for Omicron, the researchers say. Preventing Omicron infection and potential future variants may require tools beyond the currently available vaccines, the scientists conclude.
Journal/conference: JAMA Network Open
Link to research (DOI): 10.1001/jamanetworkopen.2022.32760
Organisation/s: Public Health Ontario, Canada
Funder: This work was supported by the Canadian Immunization Research Network (CIRN) through
grant CNF 151944 from the Public Health Agency of Canada and the Canadian Institutes of Health Research and
CITF-VSRG-01 from the Public Health Agency of Canada through the Vaccine Surveillance Reference Group and the
COVID-19 Immunity Task Force. This study was also supported by ICES (which is funded by an annual grant from
the Ontario Ministry of Health [MOH] and the Ministry of Long-Term Care [MLTC]), Public Health Ontario, and the
Ontario Health Data Platform (OHDP), a Province of Ontario initiative to support Ontario’s ongoing response to
COVID-19 and its related impacts. Parts of this study were based on data and/or information compiled and
provided by the Canadian Institute for Health Information (CIHI) and by Ontario Health (OH).
Media release
From: JAMA
Estimated Effectiveness of COVID-19 Vaccines Against Omicron or Delta Infection, Outcomes
About The Study: This study estimated the effectiveness of COVID-19 vaccines against symptomatic infections due to the Delta and Omicron variants and severe outcomes (hospitalization or death) associated with these infections among adults in Ontario, Canada.
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