Archived 47: Summary of National Advisory Committee on Immunization (NACI) updates of November 3, 2022: Recommendations on the use of Moderna Spikevax BA.4/5 bivalent mRNA (50 mcg) COVID-19 booster vaccine in adults

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Organization: Public Health Agency of Canada

Cat.: HP5-148/2022E-PDF

ISBN: 978-0-660-46029-1

Pub.: 220546

Published: 2022-11-03

Publication date: November 3, 2022

Notice to reader

This is an archived version. Please refer to current COVID-19 vaccine pages:


  • On November 3, 2022, Health Canada authorized the use of the Moderna Spikevax 50 mcg BA.4/5 bivalent COVID-19 vaccine as a booster dose in individuals 18 years of age and older.
  • Health Canada has previously authorized similar bivalent booster doses containing Omicron BA.1 or BA.4/5 variants from Moderna (50 mcg) and Pfizer-BioNTech (30 mcg) in September and October of 2022.
  • Available evidence suggests this new Moderna bivalent BA.4/5 formulation is comparable to other bivalent booster products already authorized and recommended for use as part of the fall 2022 COVID-19 booster program.
  • NACI continues to recommend that bivalent Omicron-containing mRNA COVID-19 vaccines are the preferred booster products for the authorized age groups. (Strong NACI recommendation)
  • Going forward, any of the bivalent Omicron-containing mRNA boosters are preferred over the original formulation boosters for authorized age groups (18 years of age and older for Moderna bivalent vaccines and 12 years of age and older for Pfizer-BioNTech bivalent vaccines).
  • Bivalent Omicron-containing mRNA vaccines are expected to broaden the immune response and provide improved protection against the Omicron variant and subvariants compared to original mRNA COVID-19 vaccines, with a similar safety profile.
  • Omicron is the most distinct variant of concern to date, with a number of key mutations distinguishing it from the original SARS-CoV-2 virus. The BA.4 and BA.5 Omicron subvariants are currently the dominant strains of the COVID-19 virus circulating in Canada.
  • Health Canada and NACI are currently reviewing whether bivalent vaccines may also be an option for boosters in children 5 to 11 years of age this fall.
  • There is currently no evidence to suggest any meaningful difference in protection between different bivalent booster vaccines targeting BA.1 versus BA.4/5, nor any clinical trials directly comparing the Moderna (50 mcg) and Pfizer-BioNTech (30 mcg) bivalent booster products. Vaccine effectiveness has not yet been established for the bivalent booster products.
  • COVID-19 booster doses this fall are an important part of the ongoing pandemic response, contact your local public health department to learn where you can receive one.

For more information on the authorization of this new bivalent booster formulation, please refer to the product monograph.

For more information on NACI’s recommendations on the use of COVID-19 vaccines, please refer to the COVID-19 vaccine chapter in the Canadian Immunization Guide (CIG), as well as additional statements on the NACI web page.

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