A new study by US health authorities published Thursday provided more data showing that, when it comes to catching Covid-19, visiting bars and restaurants is far more dangerous than going shopping, working from an office or using public transport.
It was already suspected that this was the case, but few studies have sought to rigorously establish a hierarchy of risk in public activities.
The new report by the Centers for Disease Control and Prevention (CDC) isn't perfect: it can't confirm definitively where people in the cases it studied were infected.
CDC officials approached people who had gone for a test at 11 American hospitals in July and asked them to fill out a detailed questionnaire.
Overall, about 300 participated, half of whom tested positive and the other half negative.
Participants were asked questions about possible community exposure over the previous 14 days, in settings including public transport, at private gatherings, offices, churches, salons, bars and restaurants.
They realized that the participants who tested positive and those who tested negative reported similar mask-wearing behavior and similar levels of exposure in all the settings except bars and restaurants.
"Adults with positive SARS-CoV-2 test results were approximately twice as likely to have reported dining at a restaurant than were those with negative SARS-CoV-2 test results," it found.
The risk was even higher for bars when the analysis was restricted to participants who hadn't reported exposure to a person with a known case of Covid-19.
The analysis will need further validation, particularly since it did not distinguish between indoor and outdoor drinking and dining settings.
But it is further evidence of the contamination risks associated with microdroplets that travel much further than the six feet (two meters) recommended by social distancing guidelines and can be carried along air ventilation currents.
Eating and drinking also requires people to take off their masks, which they do not need to do in other settings.