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).
· Tele-ICU services are provided either by existing staff within the network to smaller centers, or outsourced to larger networks or independent firms
· The impact of tele-ICU adoption can result in a decrease in ICU mortality as large as 32%
· The impact of tele-ICU adoption of length of stay is mixed, with some studies reporting a significant decrease, while others report a small, but statistically insignificant decrease
· The degree of impact of tele-ICU adoption is linked to several factors such as yearly admission rates, location (urban vs. rural) and level of authority given to the tele-ICU team leading to increased positive impacts.
Badea, A; Groot, G; Reeder, B; Young, C; Ellsworth, C; Howell-Spooner, B. How to deliver remote ICU care for COVID-19 patients to avoid/prevent transfer from smaller communities to tertiary care hospitals. 2021 Apr 6; Document no.: CC210301 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 13p. (CEST rapid review report)
There is limited research examining COVID-19 ICU patients undergoing prolonged (>14 days) mechanical ventilation
Rates of prolonged mechanical ventilation, defined as > 14 days, among COVID-19 ICU patients ranged from 16.7% to 33.3%.
Overall, studies suggest that length of ICU stay range from 11 to 31 days and length of hospital stay range from 25 to 51 days among COVID-19 patients who have undergone prolonged mechanical ventilation.
Following ICU discharge, patients are admitted to general wards, subacute nursing facilities, pneumological sub-intensive units, rehabilitation wards or long-term acute care.
Groot, G; McLean, M; Fox, L; Mueller, M. What is the final disposition of post-COVID patients who require chronic ventilation in the ICU? 2021 Feb 27; Document no.: CC011101 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 37 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)
· There was no source of Canadian data (published or grey, federal or provincial) to address this question and differentiate between types of ventilation.
· There are several studies available assessing the proportions seen in other countries and a lot of theoretical literature about using non-invasive ventilation (NIV) as a first-line intervention to hopefully avoid intubation and invasive mechanical ventilation (IMV), for which there is weak evidence.
· Key studies include an analysis of 36 ICU patients in Wuhan in which 41.7% received NIV and 47.2% received MIV. Another large-scale study of 1,099 hospitalized patients reported IMV in 6.1% with no report of NIV.
Badea, A; Groot, G; Dalidowicz, M; Miller, L. In similar jurisdictions experiencing the COVID-19 pandemic, what is the proportion of patients receiving non-invasive ventilation versus those receiving intermittent mandatory ventilation? 2020 May 22; Document no.: EOC052102 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 8 p. (CEST rapid review report)