Prioritizing specific neighborhoods improves public health response to COVID-19

The COVID-19 pandemic is having uneven impacts across cities and provinces, with some regions struggling more than others. Hotspots of COVID-19 infections in Canadian cities are linked to occupation, income, housing and markers of structural racism, a new study shows.

To better understand the factors contributing to the concentration of infections in specific regions, a team of researchers from across Canada, including Yiqing Xia, David Buckeridge and Mathieu Maheu-Giroux of McGill University, analyzed provincial surveillance data from January 2020 to February 2021. study, which looked at infections in 16 urban centers in Quebec, Ontario, British Columbia and Manitoba, is published in the Canadian Medical Association Journal.

Patterns of COVID-19 transmission in cities

In each of the cities we looked at, 50% of cases were concentrated in areas with less than 21% to 35% of the population. In these regions, the factors associated with the concentration of cases varied slightly depending on the local contexts.”

Mathieu Maheu-Giroux, Professor Canada Research Chair in Population Health Modeling, McGill University

“In all provinces, cases were geographically concentrated along the social determinants of health. These include neighborhoods with high-density housing, more essential workers, low-income or low-education residents, and a higher proportion of visible minorities or recent immigrants,” says the leader. . author Yiqing Xia, McGill PhD student in the Department of Epidemiology, Biostatistics and Occupational Health.

The researchers found that the most common social determinant of health across all cities was visible minority status. These findings are consistent with other studies from Canada as well as Sweden, the United States and other countries showing higher rates of COVID-19 in vulnerable communities or various neighborhoods.

During the study period, 63,266 cases of COVID-19 in British Columbia, 15,089 in Manitoba, 239,160 in Ontario and 224,377 in Quebec were recorded in the 16 metropolitan areas. They accounted for 81%, 57%, 83% and 80% of all confirmed cases in each province, respectively.

COVID-19 hotspots in Quebec

“What is striking in our analyzes is that we observe similar trends in all the Quebec cities examined: cases are concentrated according to the social determinants of health in Gatineau, Quebec, Sherbrooke, Saguenay and Trois-Rivières”, explains Mathieu Maheu-Giroux. .

“In Montreal, the local Direction régionale de santé publique has sometimes prioritized certain interventions such as testing and vaccines in specific areas of the city that have experienced high transmission of COVID-19. There is a need to scale up these initiatives to make our response to the pandemic more effective,” he adds.

Focus on populations most at risk of infection

“Understanding factors associated with geographic transmission patterns in cities can help identify populations and, in particular, settings at greatest risk,” says Dr. Sharmistha Mishra of St. Michael’s Hospital and Unity Health Toronto. “Geographical analyzes can enable better allocation of resources, adaptation of policies and implementation of context-specific strategies to curb local transmission more effectively and efficiently,” she says.

To effectively reach and meet the prevention and care needs of communities at disproportionate risk from COVID, the authors call for geographically prioritized public health supports for hotspots across the country, such as vaccination deployments and testing. in specific areas. “Prioritizing specific neighborhoods that are most at risk of transmission provides a clear path forward in the public health response to the resurgence of COVID-19,” they conclude.


Journal reference:

Xia, Y. et al. (2022) Geographic concentration of SARS-CoV-2 cases by social determinants of health in metropolitan areas of Canada: a cross-sectional study. Canadian Medical Association Journal.

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