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. 2021 Mar 25;6(2):73-78.
doi: 10.3138/jammi-2021-0323. eCollection 2021 Jun.

COVID-19 vaccination: Why extend the interval between doses?

Caroline Quach  1   2   3 , Shelley Deeks  3   4   5
Affiliations

COVID-19 vaccination: Why extend the interval between doses?

Caroline Quach et al. J Assoc Med Microbiol Infect Dis Can. .

Abstract
in English, French

On March 3, 2021, faced with ongoing morbidity and mortality from coronavirus disease 2019 (COVID-19) and insufficient supplies of authorized, available vaccines against COVID-19 in Canada, the National Advisory Committee on Immunization (NACI) issued a strong recommendation to allow for an extended interval between vaccine doses to maximize the number of people protected as quickly as possible. NACI's recommendation was released in the form of a rapid response because of the urgency of the situation and was based on a review of the evidence; principles of immunology; historical experience with vaccines; modelling studies; and consideration of ethics, equity, feasibility, and acceptability. Since then, many questions and concerns have been raised. This article aims to provide further explanation of the rationale for the decision and prepare health care providers with information they need as they support their patients in the vaccination rollout.

Le 3 mars 2021, devant la morbidité et la mortalité continues causées par la maladie à coronavirus 2019 (COVID-19) et l’offre insuffisante de vaccins autorisés et disponibles contre la COVID-19 au Canada, le Comité consultatif national de l’immunisation a publié une forte recommandation préconisant un intervalle prolongé entre les doses des vaccins, afin d’optimiser le nombre de personnes protégées le plus rapidement possible. La recommandation du comité, qui a pris la forme d’une réponse rapide en raison de l’urgence de la situation, repose sur l’examen des données probantes, les principes immunologiques, l’expérience des vaccins, les études de modélisation et les principes d’éthique, d’équité, de faisabilité et d’acceptabilité. De nombreuses questions et inquiétudes ont été soulevées depuis. Le présent article vise à mieux expliquer les motifs de cette recommandation et à fournir aux dispensateurs de soins l’information dont ils ont besoin pour soutenir leurs patients pendant le déploiement de la vaccination.

Keywords: COVID-19; interval; public health; vaccination.

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Conflict of interest statement

The authors have nothing to disclose.

Figures

Figure 1:
Figure 1:
Daily incidence of symptomatic COVID-19, hospitalizations, and deaths from the model assuming a third wave (Reff = 1.2) beginning in April 2021 Notes: Figure shows dose 1 effectiveness against symptomatic COVID-19 of 85% and effectiveness against infection of 42.5% (ie, 50% of VE disease). Deaths do not include those occurring in long-term-care facilities, which were not included in the model (A. Nam, E-mail communication, March 21, 2021). COVID-19 = Coronavirus disease 2019; VE = Vaccine effectiveness.
See this image and copyright information in PMC

References

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    1. Department of Health & Social Care. Joint Committee on Vacination and Immunisation: advice on priority groups for COVID-19 vaccination, 30 December 2020. https://www.gov.uk/government/publications/priority-groups-for-coronavir... (March 15, 2021).
    1. National Advisory Committee on Immunization. Recommendations on the use of COVID-19 vaccines. https://www.canada.ca/en/public-health/services/immunization/national-ad... (March 14, 2021).
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