Archived 5: NACI rapid response: Extended dose intervals for COVID-19 vaccines to optimize early vaccine rollout and population protection in Canada [2021-03-03]

Notice to reader

This is an archived version. Please refer to the most current version of this statement.

Publication date: March 3, 2021

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Preamble

The National Advisory Committee on Immunization (NACI) is an External Advisory Body that provides the Public Health Agency of Canada (PHAC) with independent, ongoing and timely medical, scientific, and public health advice in response to questions from PHAC relating to immunization.

In addition to burden of disease and vaccine characteristics, PHAC has expanded the mandate of NACI to include the systematic consideration of programmatic factors in developing evidence-based recommendations to facilitate timely decision-making for publicly funded vaccine programs at provincial and territorial levels.

The additional factors to be systematically considered by NACI include: economics, ethics, equity, feasibility, and acceptability. Not all NACI Statements will require in-depth analyses of all programmatic factors. While systematic consideration of programmatic factors will be conducted using evidence-informed tools to identify distinct issues that could impact decision-making for recommendation development, only distinct issues identified as being specific to the vaccine or vaccine-preventable disease will be included.

This statement contains NACI's independent advice and recommendations, which are based upon the best current available scientific knowledge.

This document is being disseminated for information purposes. People administering the vaccine should also be aware of the contents of the relevant product monograph(s). Recommendations for use and other information set out herein may differ from that set out in the product monograph(s) of the Canadian manufacturer(s) of the vaccines. Manufacturer(s) have sought approval of the vaccines and provided evidence as to its safety and efficacy only when it is used in accordance with the product monographs. NACI members and liaison members conduct themselves within the context of PHAC's Policy on Conflict of Interest, including yearly declaration of potential conflict of interest.

Summary

Introduction

Since COVID-19 vaccines were first authorized in Canada in December 2020, the National Advisory Committee on Immunization (NACI) has been providing evidence-informed guidance on the recommended interval between vaccine doses. In the most recent update, January 12, 2021, NACI provided advice on extending intervals for mRNA vaccines to six weeks. In February 2021, the Public Health Agency of Canada (PHAC) asked NACI to address the following context and question: Due to limited vaccine supply and logistical challenges, jurisdictions need to implement COVID-19 mRNA vaccine intervals beyond six weeks. Given emerging evidence as mRNA vaccines are rolled out to populations in Canada and elsewhere in the world, what extended interval would be recommended in order to balance individual protection and population impact? Are extended intervals a particular concern for any key populations?

Guidance objective

The objective of this bulletin is to provide guidance for the equitable, ethical, and efficient allocation of authorized COVID-19 vaccines in the context of staggered arrival of vaccine supply. This guidance builds on the foundational framework of NACI's Recommendations on the use of COVID-19 vaccines. The goal of Canada's pandemic response is to minimize serious illness and death while minimizing societal disruption as a result of the COVID-19 pandemic.

Methods

NACI reviewed available evidence in full Committee meetings (February 8, 2021; February 24-25, 2021) and Working Group meetings (February 19, 2021) on extended intervals for COVID-19 vaccines. This included evidence available from published peer-review studies, pre-prints, and data available from population-based assessments from within and outside of Canada. On March 1, 2021, NACI voted on and approved the revised recommendations by majority. Due to the urgency for provinces and territories to consider implementing extended dose intervals, NACI is providing an abridged rationale in this document. The complete analysis, including more detailed evidence summaries and references, will be provided in coming weeks as the NACI evergreen guideline is updated online in the Recommendations on the use of COVID-19 vaccines.

Recommendations

Based on emerging evidence of the protection provided by the first dose of a two dose series for COVID-19 vaccines currently authorized in Canada, NACI recommends that in the context of limited COVID-19 vaccine supply jurisdictions should maximize the number of individuals benefiting from the first dose of vaccine by extending the second dose of COVID-19 vaccine up to four months after the first. NACI will continue to monitor the evidence on effectiveness of an extended dose interval and will adjust recommendations as needed. (Strong NACI Recommendation)

Please note:

Summary of rationale

Due to the urgency for provinces and territories to consider implementing extended dose intervals, NACI is providing an abridged rationale in this document. The complete analysis, including more detailed evidence summaries and references, will be provided in coming weeks as the NACI evergreen guideline is updated online in the Recommendations on the use of COVID-19 vaccines.

Protecting individuals

Protecting populations

Acknowledgments

This statement was prepared by: Dr. M Tunis, Dr. B Warshawsky, Dr. M Salvadori, Dr. R Harrison, Dr. S Deeks on behalf of NACI.

NACI gratefully acknowledges the contribution of: Ms. K Young, Ms. YE Chung, Ms. K Farrah, Dr. A Nam, Ms. MW Yeung, Dr. R Ximenes, Dr. G De Serres, Dr. D Skowronski, Dr. N Andrews, and the NACI Secretariat.

NACI

Members: Dr. C Quach (Chair), Dr. S Deeks (Vice-Chair), Dr. J Bettinger, Dr. N Dayneka, Dr. P De Wals, Dr. E Dubé, Dr. V Dubey, Dr. S Gantt, Dr. R Harrison, Dr. K Hildebrand, Dr. K Klein, Dr. J Papenburg, Dr. C Rotstein, Dr. B Sander, Ms. S Smith, and Dr. S Wilson.

Liaison representatives: Dr. LM Bucci (Canadian Public Health Association), Dr. E Castillo (Society of Obstetricians and Gynaecologists of Canada), Dr. A Cohn (Centers for Disease Control and Prevention, United States), Ms. L Dupuis (Canadian Nurses Association), Dr. J Emili (College of Family Physicians of Canada), Dr. D Fell (Canadian Association for Immunization Research and Evaluation), Dr. M Lavoie (Council of Chief Medical Officers of Health), Dr. D Moore (Canadian Paediatric Society), Dr. M Naus (Canadian Immunization Committee), and Dr. A Pham-Huy (Association of Medical Microbiology and Infectious Disease Canada).

Ex-officio representatives: Dr. D Danoff (Marketed Health Products Directorate, HC), Ms. E Henry (Centre for Immunization and Respiratory Infectious Diseases [CIRID], PHAC), Ms. M Lacroix (Public Health Ethics Consultative Group, PHAC), Ms. J Pennock (CIRID, PHAC), Dr. R Pless (Biologic and Radiopharmaceutical Drugs Directorate, Health Canada), Dr. G Poliquin (National Microbiology Laboratory, PHAC), Dr. V Beswick-Escanlar (National Defence and the Canadian Armed Forces), and Dr. T Wong (First Nations and Inuit Health Branch, Indigenous Services Canada).

NACI High Consequence Infectious Disease Working Group

Members: Dr. C Quach (Chair), Dr. S Deeks (Vice-Chair), Dr. Y-G Bui, Dr. K Dooling, Dr. R Harrison, Dr. K Hildebrand, Dr. M Murti, Dr. J Papenburg, Dr. R Pless, Dr. N Stall, and Dr. S Vaughan, Dr. M Miller, Dr. S Ramanathan.

PHAC Participants: Dr. N Abraham, Dr. O. Baclic, Ms. Y-E Chung, Ms. L Coward, Ms. P Doyon-Plourde, Ms. K Farrah, Ms. V Ferrante, Dr. N Forbes, Dr. SJ Ismail, Ms. C. Jensen, Dr. A Killikelly, Dr. R Krishnan, Dr. A Nam, Mr. M Patel, Dr. M Salvadori, Ms. A Sinilaite, Dr. R Stirling, Ms. E Tice, Dr. M Tunis, Ms. E Wong, Ms. MW Yeung, Ms. K Young, Dr. J Zafack, and Dr. B Warshawsky.

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