They were not typical concertgoers, but volunteers in an elaborate study by a team at Martin Luther University Halle-Wittenberg called Restart 19. Each attendee, outfitted with a digital location tracker and hand disinfectant laced with fluorescent dye, were carefully positioned on seats as part of one of the first experiments by scientists to track the risks of coronavirus infection posed by large, indoor events…

To minimize the risk of infection, all volunteers were tested for the coronavirus in advance, and had their temperatures checked upon arrival. Outfitted with their tracking devices, masks and fluorescent disinfectant, they were then asked to simulate different concert scenarios over the course of 10 hours: one with no social distancing, another with moderate safety measures and a third with strict ones.

Each iteration included performances by Mr. Bendzko and a break, during which participants simulated trips to vendors for food and drinks and made bathroom visits. Using trackers, the staff monitored the number of times attendees came close to one another, and later used ultraviolet lamps to determine which surfaces were covered with the most fluorescent disinfectant by the end of the day.