Current recommendations suggest phased distribution of authorized vaccines and prioritization of the recipients (e.g., health care workers, frontline essential workers, and elderly population).
A concern that could exist with using AstraZeneca on critical populations is that it may have little coverage for mild-moderate B.1.351, which may have implications in transmission. This could be a concern in critical workforces if the variant becomes predominant, especially given the potentially higher transmissibility of variant. The literature is mixed but it is possible that AstraZeneca has lower efficacy than the mRNA vaccines.
Canadian National Advisory Committee on Immunization (NACI) recommends that in the context of limited vaccine supply, initial doses of mRNA vaccines should be prioritized for those at highest risk of severe illness and death and highest risk of exposure to COVID-19. On the other hand, US Advisory Committee on Immunization Practices (ACIP) recommends no product preference for the vaccines.
Just recently, NACI has expanded its recommendation for the use of the AstraZeneca vaccine to all people over the age of 18, now including those 65 years of age and over.
While Pfizer and Moderna vaccines are mRNA vaccines and need special logistical and transportation considerations, AstraZeneca and Johnson&Johnson (J&J) vaccines are viral vector vaccines that are easier to transport.
J&J is a single dose vaccine thus may be more appropriate in certain settings (such as homeless shelters and correctional facilities). Of note, there is no empirical evidence yet available to support this use; this suggestion is based simply on the nature of the vaccine.
Azizian, A; Shumilak, G; Lee, S; Reeder, B; Groot, G; Miller, L; Howell-Spooner, B. What are the differences between COVID-19 vaccines and how they should be distributed based on population group(s)? 2021 Mar 18; Document no.: EOC031001 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 19 p. (CEST rapid review report)