A third dose of vaccine against COVID-19 protects against Omicron and for any level of severity of the disease, confirms in detail a new study from the National Institute of Public Health of Quebec (INSPQ).
Protection against the risk of hospitalization increases from 80% to 90% once inoculated for a third time, indicates the short scientific opinion made public on Wednesday.
This study is based on preliminary data collected between December 26, 2021 and February 5, 2022, i.e. when the Omicron variant was dominant in Quebec.
“The effectiveness of the vaccine in preventing an emergency room consultation was approximately 60% after 2 doses and 85% after 3 doses”, mention the researchers.
Regarding the prevention of a “mild disease”, the effectiveness of the vaccine increases from 45% after 2 doses to 80% after 3 doses.
These statistical discrepancies are observed for any type of vaccine or combination thereof, with the exception of the vaccine produced by AstraZeneca. “Efficacy is slightly lower in those who received only two doses of the Vaxzevria/Covishield vaccine,” the study states.
The INSPQ results also confirm that the protection conferred by vaccines “remains rather stable” in the long term. A decrease of approximately 10% in protection against COVID-19 is observed after 32 weeks.
Nearly 45% of the Quebec population obtained a 3rd dose as of February 15.
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