Transmission of SARS-CoV-2 Variants of Concern Higher Among Low-Income Essential Workers

By Lorraine L. Janeczko

November 01, 2021

NEW YORK (Reuters Health) - As was the case with wildtype SARS-CoV-2, transmission of SARS-CoV-2 variants of concern (VOC) appears to be higher in communities where people's incomes are low and many of them are essential workers, a study of census data from Canada suggests.

"The critical finding here is that SARS-CoV-2 variants of concern transmitted rapidly among people who were unable to work remotely," study co-author Dr. Stefan D. Baral of Johns Hopkins University in Baltimore, Maryland, told Reuters Health. "Moreover, the epidemiology in terms of who was at risk for infection by variants of concern, which emerged in late 2020, was very similar to the original virus."

Dr. Baral and his colleagues conducted a retrospective cohort study of the burden of COVID-19 and VOC in neighborhoods in the Toronto area where many residents were frontline essential workers with low income and socioeconomic status and relatively high-density contact networks. During the observation period, nonessential businesses, restaurants, and fitness centers were closed, and people at home were able to interact only with others in their own household.

The research team examined Statistics Canada 2016 Census data for neighborhood-level characteristics, with each area representing around 400 to 700 residents.

They used a public-health disease database of person-level data linked with cases that tested positive on polymerase chain reaction (PCR) for the N501Y VOC between February 3 and March 10, 2021.

As reported in JAMA Network Open, of the 19,912 COVID-19 cases they found, 12,860 (64.6%) were screened for a VOC, and 5,084 (25.5%) screened positive.

Overall, 44% of total cases were in income tertile 1 (lowest), 36% were in tertile 2, and 21% were in tertile 3. Of the VOC cases, 44% were in tertile 1, 35% were in tertile 2, and 22% were in tertile 3.

In essential-worker tertiles of total cases, 48% of total cases were in tertile 1 (highest proportion of essential workers), 33% were in tertile 2, and 19% were in tertile 3. Of the VOC cases, 51% were in essential-worker tertile 1, 31% were in tertile 2, and 18% were in tertile 3.

Dr. Baral noted by email that, although the lack of data on individuals is a limitation of the study, "having a complete data set on new variants and the ability to compare these against historical data" are strengths.

"Vaccine rollouts need to prioritize low-income communities and essential workers," lead author Dr. Zain Chagla of the University of Toronto told Reuters Health by email. "Similarly, workplace controls, safety, testing, and support for paid sick leave are essential parts of pandemic control."

Dr. Baral noted that carrying out this study "was important to highlight the inequities and structural racism at play in COVID-19. These communities were the least served by the early vaccine programs because their residents did not have cars and were unable to get time off during business hours to get vaccinated."

Dr. Yelba Castellon-Lopez, an assistant professor in the Department of Family Medicine of the David Geffen School of Medicine at UCLA in Los Angeles, agreed with Drs. Chagla and Baral.

"Policies must recognize that the pandemic has devastated some communities disproportionately," Dr. Castellon-Lopez, who was not involved in the study, told Reuters Health by email. "Working successfully with the most impacted communities requires that we direct resources to and collaborate with organizations that have strong ties to the community and have established trust."

"Vaccines represent a critical tool in decreasing COVID-19 risks, but more work is needed to support vaccine uptake in historically marginalized communities," Dr. Baral added.

SOURCE: JAMA Network Open, online October 19, 2021.