Is Your Supermarket a COVID-19 Hotspot?

Among 104 workers at one Boston-area supermarket, 20% had positive viral assays for SARS-CoV-2, of whom three-quarters were asymptomatic, researchers said.

An adjusted analysis found employees with direct exposure to customers were five times more likely to test positive, albeit with a wide confidence interval (aOR 5.1, 95% CI 1.1-24.8), reported Justin Yang, MD, of Harvard T.H. Chan School of Public Health in Boston, and colleagues in Occupational & Environmental Medicine.

Moreover, the prevalence of anxiety among the workers was 24%, with a depression prevalence of 8%, they noted.

Yang’s group noted that essential workers, such as first responders and people working in retail, cannot participate in risk reduction strategies, and thus have higher potential risk of exposure. Not only that, but “they may become a significant source of transmission for the community they serve.”

But while much of the research has focused on healthcare, very few examined other essential workers. And while previous studies reported SARS-CoV-2 infections in supermarkets, “no study has examined SARS-CoV-2 exposure risks or psychological stress among grocery retail essential employees.”

The supermarket workers analyzed in the current study had undergone three days of clinical evaluation and nasopharyngeal swab testing in early May 2020. Demographic information, SARS-CoV-2-related exposure, symptoms within the last 1-2 weeks, personal protective equipment usage and mental health surveys were covered on a paper-based questionnaire prior to screening. The mental health screening tools included the Patient Health Questionnaire-9 and General Anxiety Disorder-7.

Employees’ mean age was 49, 47% were women, and 62% were non-Caucasian minorities. Among the 21 employees testing positive for SARS-CoV-2, 91% had a job with significant direct customer exposure versus 59% of SARS-CoV-2 negative employees (P=0.009). There was no statistical difference in protective behaviors such as social distancing, use of masks and/or gloves, avoiding public transportation or shared rides.

About half the workers with anxiety reported they could practice social distancing consistently at work, compared to 76% without anxiety (P=0.009).

Workers who screened positive for depression were less likely to practice social distancing consistently and more likely to commute via public transportation or shared rides, the authors found. In fact, the ability to practice social distancing consistently at work was inversely associated with both anxiety and depression.

Yang and colleagues noted the infection rate was significantly higher than the surrounding communities, where rates were all under 2%.

Limitations to the study include its small sample size and unmeasured confounders, its cross-sectional design (from which causation can’t be inferred), and most of the data other than test results came from a self-reported questionnaire.