December 6, 2021
- A new SARS-CoV-2 variant designated Omicron has emerged and classified as a VOC by WHO. The heavily mutated variant (50 mutations -- 32 of them on the spike protein) was first identified in South Africa and has already spread to many parts of the world.
- Preliminary evidence suggests there may be an increased risk of reinfection with Omicron, however, there is still emerging evidence of the transmissibility, severity of disease, effectiveness of vaccines, and the effectiveness of current tests and treatment.
- Delta dominance - Delta remains the predominant variant accounting for most of variants sequenced from surveillance data from Public Health Ontario, Public Health England and ECDC.
- The Delta sub-lineage AY.4.2 (Delta plus) continues account for an increasing proportion of Delta cases in the UK.
- Delta variant sub-lineage AY.25 and AY.27 have been detected in Canada, with majority of the cases identified in Saskatchewan, followed by Alberta and B.C. However, experts say there’s no data to determine if these sub-lineages will be more transmissible than its parent strain.
November 23, 2021
- Delta dominance - Delta continues to account for most of variants sequenced from surveillance data from Public Health Ontario, Public Health England and ECDC.
- The Delta sub-lineage AY.4.2 (Delta plus) accounts for a slowly increasing proportion of Delta cases in the UK. However, evidence is still emerging on its effect on vaccine efficacy and disease severity.
- Increased disease severity (hospitalization) has been observed in adults 18 to 49 years during Delta variant dominance and has been attributed to the low vaccination rates among this age group.
- Epidemiological models predict a new wave of infection if measures such as NPIs are relaxed due to changes in immune escape capability and transmissibility of variants.
- While of moderate certainty, evidence exists to suggest the Delta variant is associated with a higher secondary attack rate, especially among unvaccinated populations.
Asamoah, G; Badea, A; Lee, S; Shumilak, G; Reeder, B; Groot, G; Muhajarine, N; Hernandez-Ronquillo L; Miller, L; Howell-Spooner, B. What is the epidemiology of variants and what are the implications for healthcare? 2021 Dec 06. Document no.: EOC031801v018 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2021. 49 p. (CEST rapid review report).
In October, WHO released a consensus definition of post COVID-19 condition that includes 12 domains. This development should lead to better standardization of reporting and contribute to more precise prevalence estimates and better understanding of associated risk factors.
The effects of Variants of Concern (VoC) and COVID vaccination on progression of Long COVID symptoms remains unclear.
Risk factors for developing Long COVID symptoms were similar but limited evidence suggests that pre-pandemic psychological distress and poor general health were associated with developing persistent symptoms. Evidence is too limited to determine whether vaccination reduces the risk of developing Long COVID among persons with breakthrough infections.
Given the protean manifestations of Long COVID symptoms, the underlying causes are likely multifactorial; however, strong evidence to substantiate the theories of causation remains limited.
Research related to longer-term consequences of SARS CoV-2 infections in pediatric populations is growing but remains limited.
March 15, 2021
There is a lack of consensus around the clinical definition of Long COVID which in turn causes challenges with understanding the incidence and prevalence as well as the potential impact for the health care system
Information about the natural history of Long COVID is incomplete but limited evidence suggests that the immune response trajectories differ for those with few or no symptoms compared to those with severe disease. Individuals with severe disease are more likely to exhibit immunological marker abnormalities but anyone can experience functional limitations.
The mechanisms underlying the development of persistent symptoms in Long COVID remain an enigma. Despite multiple theories, there is little empirical evidence for specific immunological and or biochemical abnormalities in samples of individuals with symptoms consistent with Long COVID.
Risk factors for Long COVID include female gender, older age, higher body mass index, pre-existing asthma and the number of symptoms.
Few studies explored the short-term impact of Long COVID on health care utilization patterns and found a higher impact for those with severe disease compared with mild disease.
Williams-Roberts, H; Groot, G; Mueller, M; Dalidowicz, M. Long COVID: What does it mean for the healthcare system and programs? 2021 Oct 29. Document no.: EOC021901v2 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2021. 14 p. (CEST rapid review report).
Consequences of delayed surgeries have potential patient-level and system-level consequences
Modelling indicates that even complete resumption of services requires additional resources to clear the backlogs caused by service disruptions
Retrospective data analysis indicates that minor delays for most cancer surgeries does not negatively impact patients, however the length of time to safely delay is largely dependent on condition and urgency
Badea, A; Groot, G; Young, C; Mueller, M. What have been the consequences of delayed surgeries due to the COVID-19 pandemic? 2021 Oct 18. Document no.: EOC210903 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2021. 14 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).
Vulnerable populations such as those experiencing homelessness are 20 times more likely to be hospitalised due to COVID-19, 10 times more likely to require intensive care for COVID-19 and 5 times more likely to die within 21 days of a positive test for COVID-19
Many organizations advocate for socially vulnerable populations to be considered priority populations due to their oftencomplex health needs and inability to fully execute best practices for infection prevention and control
Past experiences from Hepatitis vaccination (requiring 3 injections) and H1N1 pandemic influenza vaccination indicate that partnering with community organizations to provide vaccinations in shelters, community centers and other frequently accessed places along with education and access to known, trusted healthcare providers greatly increase the uptake of vaccination among socially vulnerable populations
Beyond sheltered populations experiencing homelessness, considerations for equitable vaccination programs for the general population should include plans for accessibility for all, including underserved geographic regions
Badea, A; Reeder, B; Hanson, L; Miller, L; Howell-Spooner, B. What are the vaccination strategies for vulnerable populations? 2021 Mar 12; Document no.: PH030401 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 33 p. (CEST rapid review report)
Overall, data are insufficient to recommend for or against the use of ECMO in patients with COVID-19 and refractory hypoxemia.
The best available evidence points to an overall combined mortality rate of 46% among COVID-19 patients placed on ECMO (n=331). This rate is similar to the overall 40% mortality rate for extracorporeal life support in pulmonary failure. However, mortality rates among COVID-19 patients on ECMO range widely due to patient factors, site specific factors, and small sample sizes in available studies.
Recommendations for strategies and patient indications/contraindications are available to help guide centres intending to offer ECMO to COVID-19 patients.
Vanstone, J; Groot, G; Dalidowicz, M; Young, C. What are the outcomes of ECMO and COVID, particularly in small centers? 2021 Jan 13; Document no.: EOC011101 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 7 p. (CEST rapid review report)
A recent comprehensive examination of international experience  provides a hierarchy of effectiveness of public health interventions. The most effective interventions, as measured by the change in the effective reproduction number (Rt), include the cancellation of small and mass gatherings, closure of educational institutions, border restrictions, lockdowns, restrictions on individual movement, and increased availability and use of PPE such as face masks. Less effective are testing restrictions, public transportation restrictions, airport health checks, and environmental cleaning and disinfection (Figure 1).
Shelter-in-place, lockdown, and curfew orders have a substantial impact on the burden of COVID-19, having reduced Rt from 6.9 to 0.8 over the course of a month in Spain, for example. In an international comparison, stay-at-home orders reduced the percent daily increase in new cases from baseline from 26.9% at baseline to 20.3%, 12.8%, 7.3% at 7, 14, 21 days, respectively.
Closure of schools and workplaces are associated with a modest reduction in the incidence of COVID-19, in the order of 13%.
Travel restrictions lead to a moderate reduction COVID-19 disease burden. A study of 13 European countries found that voluntary reduced mobility occurring prior to government policies decreased the percent change in deaths per day by 9.2%, whereas subsequent government closure policies decreased deaths per day by 14.0%.
An extensive systematic review of SARS, MERS, and SARS-CoV-2 demonstrates that physical distancing of 1 m is associated with a relative risk (RR) of disease transmission = 0.18. The RR decreases two-fold for each additional m increase in distance.
A ban on public gatherings reduces COVID-19 transmission; however, evidence supporting specific gathering size limits is weak. In Germany, gathering restrictions and voluntary behaviour changes had the single greatest effect on the epidemic, reducing Rt by 9.7% per day and the growth rate from 30 to 12% within 2 weeks. Findings from the UK lockdown indicate that the average daily number of contacts decreased from 10.8 before to 2.8 after the lockdown. This was associated with a decrease in Rt from 2.6 to 0.62.
In a systematic review and in modelling studies, mask use by the public is estimated to reduce COVID-19 incidence and deaths by 38% and 47%, respectively.
McCarron, M; Karreman, E; Okpalauwaekwe, U; Henderson, R; Reeder, B; Muhajarine, N; Neudorf, C; Groot, G; Miller, L; Howell-Spooner, B. Which public health interventions are (most) effective in reducing the burden of COVID-19 disease in predominately OECD countries? 2021 Jan 11; Document no.: PH111001 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 54 p. (CEST rapid review report)
· There is little literature on the performance of triage frameworks. However, critiques of frameworks can help to inform the development of future protocols.
· It is ethically problematic to include age as a triage factor rather than the more nuanced factors of frailty and chronic comorbidities.
· The public should be included when creating triage protocols to create transparency and trust in the health system.
· Healthcare providers should be familiar with the ethical decisions that have been made in establishing the protocols. However, using a triage team to make decisions about resource allocation would alleviate moral burden from clinicians.
· Regular review of current guidelines, such as the use of SOFA scores, is recommended as knowledge about COVID-19 changes.
Rapid Review Report: CC120401 RR (Version 1: December 17, 2020 11:45) 2
· Patients should be regularly reassessed to allow for timely redistribution of critical resources.
Fick, F; Valiani, S; Miller, L; Howell-Spooner, B. Does data exist on the performance of triage or resource allocation frameworks for COVID-19 and other pandemics? 2020 Dec 17; Document no.: CC120401 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 91 p. (CEST rapid review report)
Physician and nursing staff members can be redeployed from various clinical areas, but in particular non-acute or elective practice areas such as ambulatory settings and surgical practices.
Providing patient-care in new clinical areas can be restructured into a task-based format that utilizes the skills already possessed by redeployed clinicians and staff.
Medical students, residents, internationally trained medical graduates and other health professionals such as respiratory therapists and pharmacists should also be considered for redeployment to high-need areas.
Scope of practice limitations, practice permit approvals and licensing may pose as potential barriers to being able to optimize our healthcare workforce in a surge.
Efficient but effective training should be provided to all staff that have volunteered for redeployment, in preparation of the next surge.
The safety of all health professionals should be ensured throughout the redeployment process.
Radu, L; Badea, A; Groot, G; Fox, L; Howell-Spooner, B; Young, C. What are the existing policies for the re-deployment or deployment of healthcare workers whose regular work has been disrupted by COVID-19 in high-resource clinical settings? 2020 Jul 29; Document no.: EOC072701 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 16 p. (CEST rapid review report)
Tupper, S; Ward, H; Howell-Spooner, B; Dalidowicz, M; What are the impacts on the family unit from visitation restrictions during an infectious disease outbreak and how can we support the families? 2020 May 14; Document no.: LTC042403 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 38 p. (CEST rapid review report)
Visitor restrictions in long-term care (LTC) during an outbreak or pandemic are implemented due to the perceived risk of transmission between residents or staff and visitors.
· Social isolation and possible loss of care resulting from visitor restrictions in LTC may place residents at risk of poorer outcomes in terms of both physical and mental health, as well as distress to families and staff (see Saskatchewan LTC Network Family Perspective).
· Visitor restriction policies typically allow visits for compassionate reasons that include end of life, critical care, and support of persons who require assistance beyond that provided by healthcare e.g. support for feeding, mobility, or behaviors, but specific detail on these is not consistent or clear.
· Recent changes to visitation policies in Australia are less restrictive and allow brief visitations (end of table 1, noted in red font).
· Although the majority of policies describe a need for flexibility and case-by-case assessment of visits deemed “essential”, the majority of policies are not clear in who is to conduct this analysis or the criteria that should be used to make these decisions.
Visitation policies differ in detail regarding the number of visitors allowed at one time, total number of visitors allowed, visit duration, mobility within the home and location of the visit.
· Remote and technology assisted visits are to be facilitated by LTC staff.
· Infection control practices are enforced for visitors, and may include screening (e.g. temperature, symptoms, travel and contact history), prohibiting ill visitors, use of personal protective equipment (PPE), hand and cough hygiene.
· Education of visitors and support for proper infection control practices is encouraged in the majority of policies.
Tupper, S; Ward, H; Howell-Spooner, B; Dalidowicz, M; Boden, C. How is "compassionate visit" defined and operationalized in the context of an infectious outbreak or pandemic in long-term care? 2020 May 1; Document no.: LTC042402
RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 17 p. (CEST rapid review report)
Badea, A; Groot, G; Dalidowicz, M; Young, C. What is the evidence for the effectiveness of face masks for preventing the spread of COVID-19 in the community? 2020 Apr 6; Document no.: EOC040601 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 8 p. (CEST rapid review report)