(NBC News) — Around 5,000 music fans in France crowded together this weekend for an indoor rock concert, which also served as a COVID-19 experiment.
Concertgoers had to wear masks and take COVID-19 tests before and after the event.
The Paris Hospital Authority devised the test to assess how concerts can resume as France gradually ends its coronavirus restrictions.
Another 25,000 people in a control group stayed home to see if the virus spreads among those attending the concert.
The results of the experiment will be disclosed by the end of June.