Three seemingly healthy families were struck by COVID-19 in January after dining at neighboring tables in a windowless restaurant in Guangzhou, China. Researchers studying the case think that the restaurant’s air-conditioner blew the viral droplets of one person who was asymptomatic farther than they might have normally gone. Nine other people across the three families later got sick. The researchers described their findings in an early-release research letter published in the journal Emerging Infectious Diseases earlier this month. You can see a diagram of the seating plan here. It’s a frightening prospect for people trying to keep a healthy distance from others. But in a potentially hopeful finding for the locked-down restaurant industry, none of the 73 other diners and eight employees in the restaurant at the time got sick, the researchers added.