This section lists and describes scientific evidence on COVID-19 outcomes among priority populations and settings, as well as recommendations from national and international health authorities, grey literature, and news articles.

Scientific Evidence

Essential workers

Health care occupations

• Health care occupations at highest risk include those in the dental health field (i.e., dental hygienists, oral and maxillofacial surgeons, dental assistants, dentists). The second highest risk category includes workers in the general health care field: general practitioners, orderlies, registered nurses and radiation therapists.

• EMS personnel are at a higher risk of dying from COVID-19 than other health care or emergency services professionals (registered nurses, fire fighters). COVID-19 related death among EMS personnel is about three times higher than that of nurses, and about five times higher than that of physicians.

Non-health care occupations

• Among non-health care occupations, workers at highest risk include: municipal firefighters, correctional officers and jailers, ambulance drivers and attendants (excluding emergency medical technicians), and firstline supervisors of correctional facilities.

Congregate Living Settings

Correctional facilities

• A Canadian study reported that fewer COVID-19 tests were being used in federal penitentiaries compared to use in the general population; between March 30 and April 21, 2020, there were outbreaks in five penitentiaries, with a COVID-19 prevalence of 30-40%.
• In Canada, Indigenous women represent over 41% of federally incarcerated women and are more likely to have higher rates of chronic conditions, including respiratory illnesses, substantially increasing vulnerability to COVID-19 complications.
• A US study (2020) found that 34 prison systems have case rates per 1,000 that are higher than the general population with the highest being in New Jersey at 159 cases per 1,000 incarcerated people.

Homeless shelters

• A pilot study in Hamilton, Ontario reported that one of 104 residents (1.0%) and seven of 141 staff (5.0%) were diagnosed with COVID-19 infection during the study period (March 19 to April 30, 2020). In comparison, the city of Hamilton reported 422 patients with COVID-19 and a positivity rate of approximately 5-7%. Researchers suggest these findings demonstrate that accessible shelter housing that provides rapid testing, isolation, and physical distancing is imperative to outbreak prevention in shelter settings.
• Multiple US studies identified high proportions of test positivity in shelters with identified clusters and evidence for pre-symptomatic and asymptomatic transmission of SARS-CoV-2 across the shelters, indicating increased risk in this setting. 44.8% of persons who were positive for SARS-CoV-2 were more frequently 60 years of age or older than those without SARS-CoV-2 (15.9%). Findings indicate that COVID-19 can spread quickly in homeless shelters; rapid interventions are necessary, including testing to identify cases and isolation to minimize transmission.
• A study in England determined that SARS-CoV-2 outbreaks in homeless settings can lead to a high attack rate among people experiencing homelessness, even if incidence remains low in the general population. Avoiding deaths depends on transmission prevention within homeless settings, including hostels and night shelters.

Residential care for people with intellectual and developmental disabilities (IDD)

• Multiple US studies suggest that compared to the general population, people with IDD living in residential group homes are at greater risk of severe COVID-19 outcomes, including fatality. Researchers found that among COVID‐19‐positive individuals with IDD, a greater likelihood of hospitalization was associated with a higher number of chronic medical conditions and male gender.

Mental health and group home facilities

• A US study identified that adolescents (11-17 years) in psychiatric inpatient settings may be especially vulnerable to COVID-19 infection.

• A study from China found that psychiatric inpatients may be more susceptible to severe viral outbreaks due to the crowded living conditions and patients’ potential disordered mental state, poor self-control and self-care, and inadequate insight; such patients may be incapable of practicing infection control measures to protect themselves.

Refugee shelters and living facilities for migrants

• An Ontario study reported that of the 60 adult residents who agreed to be tested, 41.7% were positive for COVID-19. Of those tested positive, 20% reported fever, cough or shortness of breath at the time of testing. This demonstrates the high risk of SARS-CoV-2 transmission in congregate living settings and the importance of mobilizing timely testing and management of symptomatic and asymptomatic residents in shelters.

Vulnerable Populations

Low-income and immigrant communities

• Local health unit data in Ontario suggests that vulnerable populations, including low income and immigrant communities, are more adversely affected by COVID-19 and have higher case rates, and hospitalizations.
• A 2021 Ontario based study found that certain characteristics signal higher case fatality for certain populations. For community-dwelling individuals, increased age, male sex, history of prior hospital admissions in the past three years, certain chronic medical conditions, and residing in lower-income neighbourhoods were associated with increased risk of death following COVID-19 infection.

Racialized communities

• International data from the US suggest that racialized communities, including Black and Hispanic communities, are more adversely affected by COVID-19 and may experience higher case rates and higher mortality rates. Studies attribute this to social conditions, structural racism, and structural inequalities.
• A US study found that systemic social inequities have resulted in the overrepresentation of Hispanic and non-White workers in frontline occupations where exposure to SARS-CoV-2 might be higher. Findings indicated that 73% of workplace outbreak-associated COVID-19 cases were among persons who identified as Hispanic or non-White.
• A US based study on racial disparities in COVID-19 disease reported that the 20% of US counties that are disproportionately Black account for 52% of COVID-19 diagnoses and 58% of COVID-19 deaths nationally. The study attributes this to social conditions, structural racism, and structural inequalities.
• A 2020 US study on COVID-19 mortality and occupational differences across racial/ethnic groups and US states reported that mortality was higher among non-Hispanic (NH) Black persons compared with NH White persons, due to more NH Black persons holding essential worker positions.
• Among US rural counties, the average daily increase in COVID-19 mortality rates has been significantly higher in counties with the largest shares of Black and Hispanic residents.
• A US-based study that examined COVID-19 disparities reported that Black adults at high risk for severe illness were 1.6 times as likely as White adults to live in households that contain health-sector workers. Among Hispanic adults at high risk for severe illness, 64.5% lived in households with at least one worker who was unable to work from home, versus 56.5% among Black adults and only 46.6% among White adults.

People living with mental illness

• A 2020 US study indicated that individuals with a recent diagnosis of a mental disorder are at increased risk for COVID‐19 infection, which is further exacerbated among African Americans and women; in addition, they have a higher frequency of adverse outcomes.

People who use drugs or have substance use disorders

• Individuals with substance use disorders, especially individuals with opioid use disorders and African American users, were found to have increased risk for COVID-19 infection and its adverse outcomes.

People who experience homelessness

• An Ontario study reported that people with a recent history of homelessness were over 20 times more likely to be admitted to hospital for COVID-19, over 10 times more likely to require intensive care for COVID-19, and over five times more likely to die within 21 days of their first positive test result.

Indigenous Populations

• Data from the US indicate that in 23 states with adequate race/ethnicity data, the incidence of COVID-19 among NH American Indian and Alaska Native populations was 3.5 times that of NH White persons.
• The Indian Health Service of the US has found that the Navajo Nation is amongst the hardest hit reservations in the US, with a higher per capita rate of infection than any US state, including New York, and even greater than that of Wuhan at the peak of the outbreak in China.

International Scan

Essential Workers

Health care occupations

• A 2020 European Centre for Disease Prevention and Control (ECDC) report suggests that most clusters and outbreaks in European countries were from the health and social care settings (i.e., acute care hospitals) in which the size of cluster ranged from two to 571 confirmed cases. Among these clusters, a total of 3,298 health care professionals were reported to have been affected, including 82 deaths.

Non-health care occupations

• Among non-health care workers, clusters and outbreaks were observed in the following occupational categories: office settings; educational facilities; food production, including agriculture; factory/manufacture sector; building and construction sites; packaging/mail distribution centres; bars and restaurants; and transportation sectors. In 13 European countries and the US, the food production sector (i.e., agriculture, meat and poultry processing facilities) had the highest number of COVID-19 clusters and cases.

Congregate Living Settings

Correctional facilities

• A 2020 ECDC technical report stated that, as of April 2020, there had been a number of cases in European prison settings: Italy (131 staff, 21 inmates), Spain (69 staff, six inmates), France (114 staff, 48 inmates), Belgium, Germany, and Portugal. In England and Wales, as of May 31, 2020, 466 inmates across 79 prisons and 949 staff members across 105 prisons had been confirmed COVID-19 positive, with 23 deaths among inmates and 11 among staff.

Vulnerable Populations

Racialized communities

• A UK analysis of news articles reported that of the 12,593 patients who died in hospital prior to April 19, 2020, 19% were Black, Asian and minority ethnic (BAME); these groups comprise 15% of England’s general population. Three London boroughs with high BAME populations were among the five local authorities with the highest death rates in hospitals and the community.

Indigenous Populations

• A New Zealand academic paper produced by the Department of Public Health at the University of Otago on mitigating the risk of COVID-19 among Māori citizens reported the necessity of ensuring health equity in all levels of decision‐making and in all strategies. Themes include: 1) socioeconomic inequities and social determinants of health leading to increased transmission; 2) severity of potential health impact due to underlying health conditions; and 3) existing inequities in health care access and quality that will likely increase if services become overloaded.

Canadian Scan

Vulnerable Populations

• Toronto Public Health data suggest the COVID-19 pandemic is more adversely affecting people with lower incomes, alongside new immigrant populations.

Low income populations

• When analyzed by income group, low income populations had 113 cases per 100,000 people, compared to 73 cases per 100,000 people in the highest-income group. There were 20 hospitalizations per 100,000 people among those living in the lowest income areas, compared to nine per 100,000 in the highest income areas.
• New immigrants

• When analyzed by new immigrant data, the group with the highest percentage of recent immigrants also had the highest rate of COVID-19 cases, with 104 per 100,000 people. The group with the lowest percentage of recent immigrants had the lowest rate, with 69 cases per 100,000 people.

Ontario Scan

Congregate Living Settings

Correctional facilities

• A 2020 Public Health Ontario rapid review found that, as of May 6, 2020, Correctional Services Canada reported 294 confirmed COVID-19 cases in federal correctional institutions, including 166 in Quebec, eight in Ontario, and 120 in British Columbia. As of April 21, 2020, the US CDC reported 4,893 cases and 88 deaths among incarcerated and detained persons, and 2,778 cases and 15 deaths among staff members.

Refugee shelters and living facilities for migrants

• A 2020 CBC news article reported 1,276 positive cases of COVID-19 among farm workers as of November 25, 2020 in Windsor-Essex County and two deaths. As of November, there were 147 cases among farm workers in the municipality of Chatham-Kent, most of which were attributed to an outbreak at a single greenhouse facility. Most of the farm workers infected were migrant workers living in congregate settings.

Mental health and group home facilities

• According to data from the Ontario’s Ministry of Children, Community and Social Services, four children living in group homes and foster care, and eight staff members working at group homes and youth detention facilities, tested positive for COVID-19 as of May 2020.

The COVID-19 Evidence Synthesis Network is comprised of groups specializing in evidence synthesis and knowledge translation. The group has committed to provide their expertise to provide high-quality, relevant, and timely synthesized research evidence about COVID-19 to inform decision makers as the pandemic continues.