A new study has warned that supermarket workers are up to five times more likely to test positive for coronavirus.
Researchers also found that up to 75% of staff testing positive showed no symptoms, reports The Mirror.
In the study, the team studied 104 employees at a supermarket in Boston.
Each employee completed a questionnaire on their lifestyle, medical history and employment history, before being tested for coronavirus.
The results found that one in five workers tested positive for coronavirus - and 76% of them had no symptoms.
Worryingly, of those testing positive, 91% had a customer-facing role.
In the study, published in the BMJ, the researchers said: "Once essential workers are infected with SARS-CoV-2, they may become a significant transmission source for the community they serve."
The surveys also showed that several supermarket workers reported mental health issues as a result of the pandemic.
Around 24 workers reported at least mild anxiety, while eight were deemed to be mildly depressed.
The researchers added: "Our significant mental health finding calls for action in providing comprehensive employee assistance services to help essential workers cope with the psychological distress during the Covid-19 pandemic."
Based on the findings, the researchers suggest that measures should be put in place to make supermarkets safer for both workers and customers.
