Omicron first detected in Botswana and South Africa at the end of November 2021, classified as a variant of concern by the WHO and CDC by December 1st, 2021 after rapid spread to multiple areas of the world, and evidence of community transmission
Preliminary data indicates increased transmissibility of Omicron compared to the currently dominant Delta
In-vitro data indicates a significant reduction in neutralization titers of vaccinee sera – however, sera from individuals recently boosted with an mRNA vaccine had a minimal reduction in neutralization capacity compared to Delta
Increasing rates of breakthrough infections in South Africa and the UK confirming suspicions of decreased vaccine effectiveness of primary vaccine series, early data shows that mRNA boosters increase levels of protection, though still lower than protection against other variants
Vaccination protection against severe disease appears to still be quite good, however severe disease/death are lagging indicators and a definitive conclusion cannot be made at this time
Most therapeutic monoclonal antibodies currently approved by FDA and in use do not neutralize Omicron, however therapies targeting the host immune response are anticipated to retain effectiveness
Badea, A; Reeder, B; Groot, G; Miller, L. What is the epidemiology of the Omicron variant and its impact on health care? 2021 Dec 22, Document no.: EOC211220 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2021. 10 p. (CEST rapid review report).
December 20, 2021
- 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 as of the 6th of December; this is rapidly changing.
- Expect opinions from PHAC indicate that Omicron will likely outpace Delta and drive infections up to 26,600 a day by mid-January in Canada.
- ECDC projects Omicron could cause over half of all SARS-CoV-2 infections in the EU/EEA within the next few months, with probability of further introduction and community spread and impact of the spread assessed HIGH and VERY HIGH respectively.
- Preliminary evidence suggests that the various mutations in Omicron may increase transmissibility and replication; increase evasion of antibody neutralization by COVID-19 infection, vaccine-based, or monoclonal-based antibodies; increase the binding affinity of the virus to the ACE2 receptors on host cells; and may be associated with increased infectivity.
- Evidence is still emerging on the disease severity with omicron compared to Delta, however the first Omicron death has been reported in the UK during the week of December 13, 2021.
- The Delta sub-lineage AY.4.2 (Delta plus) continues account for an increasing proportion of Delta cases in the UK, with cases detected in Canada.
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.
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 20. Document no.: EOC031801v019 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2021. 50 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).
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)
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)
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)