Long COVID-19 is likely to increase healthcare demands across the health system, including emergency departments, hospital admissions, primary care visits, specialists appointments, and home care and rehabilitation services.
The clinical care burden of long COVID-19 is the greatest in the first 3 months after testing and is likely to place the greatest demand on primary care services.
Patients with severe COVID-19 illness are more likely to place longer-term demands (4-6 months) on specialist care due to respiratory, circulatory, endocrine, metabolic, psychiatric and unspecified conditions.
McLean, M; Williams-Roberts, H; Reeder, B; Howell-Spooner, B; Ellsworth, C. What are long COVID's demands on the healthcare system, and its severity of the illness? 2021 Jul 12, Document no.: EPM210602 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2021. 23 p. (CEST rapid review report).
The frequency of Long COVID symptoms varies widely across studies based on populations studied, duration of follow up and methods of assessment of symptoms.
It is estimated that 1 in 50 persons experience Long COVID symptoms after 12 weeks; however, higher estimates up to 80% have been reported in studies with a greater proportion of persons who were previously hospitalized. A recent study of a mixed cohort of 96 persons found that only 22.9% had no symptoms at 12 months post diagnosis.
A wide range of symptoms affecting multiple organ systems has been reported. For many persons symptoms improve over time while others experience persistent and/or new symptoms. Among studies with the longest duration of follow up, the most frequently reported symptoms included fatigue (up to 65%), dyspnea (up to 50%), headache (up to 45%), anosmia/ageusia (up to 25%), cognitive memory/concentration (up to 39.6%) and sleep disorders (up to 26%).
Few studies estimated the duration of symptoms with estimates ranging from 2.2% for 6 months and 27% for 7-9 months.
The mechanism(s) leading to Long COVID remain unclear but those experiencing post acute sequelae tend to be older, have a greater number of symptoms during the acute phase of illness or manifest specific symptoms and live with multiple comorbid conditions such as obesity.
The lack of consensus on a definition of Long COVID contributes to marked variations in robust prevalence estimates.
Williams-Roberts, H; Groot, G; Reeder, B; Howell-Spooner, B; Ellsworth, C. What is the incidence and duration of Long COVID cases? 2021 Jul 09, Document no.: EPM210601 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2021. 19 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)
· 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)