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)
No scientific evidence was found to support limits of a specific number of visitors. The Newfoundland/Labrador visitor policy referred to evidence supporting restrictions to 6 contact persons including one designated support person and 5 visitors; however, supporting references were not provided (25; 4.1).
The majority of Canadian and international visitation or family presence policies differentiate between general visitors (those attending for social visits) and designated support persons (essential care providers involved in physical, psychosocial, behavioral, cultural, or language support).
Designated support persons are not limited in duration, timing, or frequency of access to resident (3, 7, 9, 11, 12, 14, 16, 24, 26).
The majority of policies limit the number of general visitors to 2 persons. These visits typically have to be scheduled and may be restricted if there is an outbreak, if the resident is COVID+, or if community transmission is high. General visitors are usually not restricted during end of life or other compassionate care reasons.
Although modeling data supports contact restrictions as an effective measure to reduce infection spread, contact restriction can be achieved with infection prevention and control measures of micro-distancing, including hand and respiratory hygiene, physical distancing, and mask use (49). Family presence in LTC can support efforts to reduce resident wandering, micro-distancing, and hand hygiene.
There continues to be no scientific evidence that family presence increases risk of infection spread into and throughout LTC homes (1, 2, 44, 46)
No evidence was found that examined adherence of family caregivers to IPAC practices. A self-report survey of visitors and staff in 87 LTC homes in Hong Kong found that visitors self-reported high compliance with most infection prevention measures despite only one quarter of homes providing education (50). Low knowledge was identified as a primary barrier for infection prevention for visitors.
Education materials have been developed in several jurisdictions for family caregivers regarding COVID-19 IPAC best practices (4, 6, 8, 28).
No evidence was found regarding the impact of staff or family caregiver education on COVID-19 infection or transmission in LTC homes.
Ward, H; Tupper, S; Miller, L; Boden, C; Mueller, M. What is the evidence regarding limiting patient visitors in long-term care facilities to 2 or less, and how are other jurisdictions managing family caregivers? 2020 Dec 4; Document no.: LTC101501 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 35 p. (CEST rapid review report)