Emerging evidence suggesting waning levels of immune markers with time, particularly against more virulent variants. How this will correlate to functional immunity is yet to be documented.
Immunocompromised populations with lower levels of responses to standard 2-dose regimens may benefit from a 3rd dose of mRNA vaccine as a part of the primary series, though their response may still be lower than what is expected in the general population
Current recommendation for populations to receive a 3rd dose include adults over a certain age (depending on jurisdiction), those living in long-term care settings, frontline health and social workers and/or people working in high risk settings, those with immune compromising conditions leading to increased risk of severe disease/poor outcomes if infected
Safety trials have indicated that side effects to 3rd/booster doses are similar to those following the 2nd dose in initial vaccination series
Badea, A; Groot, G; Muhajarine, N; Lee, S; Shumilak, G; Hernandez-Ronquillo, L; Tian, K. What is the current evidence and recommendations regarding COVID-19 vaccine booster shots (exceeding 2 doses) for the general population? 2021 Oct 07, Document no.: EOC210902 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2021. 8 p. (CEST rapid review report).
Requiring proof of vaccination for entry into another country is not a new idea. There are regulations that need to be followed to set up a “vaccine passport” in relation to international travel (International Health Regulations (IHR) (2005))
At present the World Health Organization does not recommend vaccine passports for international travel, but they are working on a standard Smart Vaccination Certificate technical specification and standards to allow for harmonised processes to include COVID-19 vaccines into an updated version of the IHR (2005)
Countries around the world are beginning to put vaccine passports into place for international travel, as well as in some countries within country travel and access to services or businesses including Israel, France, Italy, Denmark, and the EU
The Canadian Federal government is supportive of a vaccine passport for international travel but recognize the issuing of vaccine passports will need to be province led
As of May 13, 2021, the province of Quebec has begun issuing a downloadable QR code that individual can keep on their smart phone.
As of June 9, 2021, the Federal government of Canada discussed easing restrictions for fully vaccinated Canadian citizens returning to the country
Ethical considerations in the use of vaccine passports include equitable access to vaccination (domestically and internationally), access to technology (eg. Smartphone passports), marginalization, or stigmatization especially among historically racialized groups, and socially isolated populations
Legal considerations include
o Clarifying who has the legal authority to require proof of vaccination,
o Ensuring that if new legislation is created and implemented it is in line with all pre-existing legislation (Charter of Rights and Freedoms, Human Rights Codes, privacy legislation, employment legislation),
o Ensuring that, if created by the government, there is coordination of the Provincial and Federal governments for international travel with respect to jurisdictional overlap, security of information, fraud
Health care facilities should be able to legally enact vaccination policies for patient-facing employees so long as they allow for exemptions due to medical inability or bona fide religious, or conscientious beliefs
Six in ten Canadians (61%) expect vaccine passports to be widely used in Canada by the end of 2021, the same proportion (61%) of Canadians also agreed that only vaccinated people should be allowed to engage in events involving larger crowds such as public transit, air travel, or attending cultural and sports events
Lashta E, von Tigerstrom B, Reeder B, Groot G; Miller, L; Mueller, M. What are the ethical/legal aspects of vaccine requirements? 2021 Jun 21, Document no.: EOC210503 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2021. 25 p. (CEST rapid review report).
The group designated in Saskatchewan as Clinically Extremely Vulnerable (CEV) is a heterogenous clinical population with factors that impair their immune response to differing degrees.
Very Limited evidence is currently available to assess the immune response following vaccination is selected clinical populations; no evidence is available to assess vaccine efficacy or effectiveness in these populations. The clinical relevance of measured immune response with respect to protection from disease is still uncertain.
In considering the immune response of the CEV population, it is recommended that the absolute difference in immune response between 1 and 2 doses be considered, as it is possible some patient groups will have lowered protection regardless of vaccine strategy.
In terms of clinical subgroups:
oOrgan transplantation recipients on immunosuppressive medication: solid organ transplant recipients receiving anti-metabolite maintenance immunosuppression therapy were less likely to develop an antibody response to an mRNA vaccine, compared to those receiving other types of therapies (37% vs 63%). In a study of 242 kidney transplant recipients on immunosuppressive therapy only 10.8% became seropositive at 28 days after a single dose of mRNA vaccine.
oCancer: A study of 151 elderly patients with solid and hematological malignancies and 54 healthy controls who received one or two doses of BNT162b2 (Pfizer-BioNTech) vaccine shows approximately 39% of solid cancer patients, 13% of hematological cancer patients, and 97% of healthy controls (p<0.0001) developed anti-S IgG 21 days following a single dose vaccine. However, response in solid cancer patients increased to 95% within 2 weeks of the second dose at 21 days.
oOther immunocompromising conditions (e.g., auto-immune disorders and therapy): some level of immunity is generated with vaccination; however, what this means clinically is unknown. It seems that ensuring the dosing is properly timed around biologic therapy is important.
Azizian, A; Lee, S; Shumilak, G; Groot, G; Reeder, B; Miller, L; Howell-Spooner, B. What are the risks or benefits of extended intervals between doses of COVID-19 vaccines compared to recommended dosing in extremely vulnerable populations? 2021 Apr 20, Document no.: EOC210302 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2021. 15 p. (CEST rapid review report).
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)
· Recommended to use existing vaccination structures and delivery services as much as possible for distribution of the COVID-19 vaccines
· Important to consider cold-chain requirements when developing distribution plans
· Should consider alternate locations for hard-to-reach populations that are easily accessible and familiar
· Consider branching out to mobile vaccination (e.g. home visits, door-to-door), pharmacies, workplaces, congregate living facilities, walk-up/drive-through mechanisms for vaccine delivery
Badea, A; Groot, G; Mueller, M; Howell-Spooner, B. How are other jurisdictions distributing COVID-19 vaccines in non-healthcare worker environments and what is the rationale for those distribution models? 2021 Jan 19; Document no.: PH011401 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 17 p. (CEST rapid review report)
· Well established that older individuals, particularly those with pre-existing conditions are at increased risk of severe disease and/or complications with SARS-CoV-2 infection, and volunteers should take this into consideration
· No other evidence specific to healthcare workers or volunteers to guide age restriction policies
Badea, A; Groot, G; Miller, L; Mueller, M. What are the age restrictions for healthcare workers/volunteer? 2020 Oct 19; Document no.: EOC100801 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 8 p. (CEST rapid review report)
· The CDC does not recommend universal symptom screening (all students in K-12 grades) to be done by schools prior to entry
· Schools/districts should individually work with public health officials to determine the necessity and details of implementing any testing strategies
· European CDC recommends that all symptomatic individuals and asymptomatic high-risk close contacts should be referred for testing – fast and effective contact tracing following testing is key
· Large scale universal testing in school settings has not been studied and it’s efficacy compared to implementation of other infection prevention control measures is unknown
· Large scale testing in school settings to date has largely been done in response to an outbreak, not as routine surveillance
Badea, A; Muhajarine, N; Howell-Spooner, B; Mueller, M. What laboratory surveillance testing strategies are effective for COVID-19 in school settings? 2020 Aug 27; Document no.: PH082501 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 23 p. (CEST rapid review report)