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Essential workers in supermarkets are at a much higher risk of coronavirus infection than the general population, with those in customer-facing roles being five times more likely to be infected.
Researchers in the US and Taiwan also found that, of those testing positive for SARS-CoV-2, the virus that leads to Covid-19 infection, three quarters had no symptoms.
While many studies have looked at infection rates among healthcare workers, few have looked at the prevalence of Covid-19 among frontline retail staff. The research, published in Occupational & Environmental Medicine, also looked at the psychological impact on workers.
Researchers at Harvard University’s TH Chan School of Public Health studied 104 grocery store employees in Boston who were tested for SARS-CoV-2 as part of the city’s mandatory testing regime in May 2020.
One in five (21%) were found to be infected, 76% of whom were asymptomatic. Furthermore, over 90% of those testing positive worked with “significant direct exposure” to customers.
Managers, with exposure from both customers and colleagues, also had increased risk of SARS-CoV-2 possibly due to frequent interpersonal contact, leading to higher infection rates.
The researchers acknowledged that their study had limitations, including a relatively small sample size and the analysis happening at a single point in time, but because the participants were restricted to grocery retail employees from one store this could eliminate confounding factors such as socio-economic status.
Fan Yun-Lan, a doctor at National Cheng Kung University in Taiwan, and his colleagues at Harvard said: “This is the first study to demonstrate the significant asymptomatic infection rate, exposure risks, and associated psychological distress of grocery retail essential workers during the pandemic. Once essential workers are infected with SARS-CoV-2, they may become a significant transmission source for the community they serve.”
Previous research has found the prevalence of anxiety among healthcare workers has ranged from 20% to 65% during the Covid-19 pandemic, but 24% of these workers in the Boston supermarket had at least mild anxiety, suggesting that other essential workers experience similar levels of psychological distress. The inability to practice social distancing consistently at work was a significant risk factor for anxiety and depression among the participants.
“While we are unable to discern the direction of the effect due to the cross-sectional nature of this study, these mental health findings support the need to implement further preventive strategies and to provide additional mental health assistance to essential employees,” said the authors.