Researchers in Spain have found “no sign” of higher levels of infection among people who took part in a large test concert last month.
Six people tested positive within 14 days of attending the gig in Barcelona, but the incidence was lower than that seen in the general population.
Around 5,000 music fans took part in the experiment after testing negative for Covid-19.
Revellers wore masks but did not have to socially distance.
Of the six people who tested positive, researchers concluded that four of them were infected elsewhere, not at the event itself.
Spanish authorities let the show, featuring band Love of Lesbian, go ahead as part of a research project.
The rate of infection among attendees was half the rate of people of the same age in Barcelona, researchers found.
“There is no sign that suggests transmission took place during the event,” infectious disease specialist Josep Maria Llibre told a news conference on Tuesday.
The band involved in the experiment, Love of Lesbian, thanked the event’s organisers and scientific advisers.
“We hope that from now on, after these excellent results, the world of culture will be listened to as it deserves to be,” it tweeted.
The concert was one of the largest gatherings in Europe since the pandemic began and comes as countries across the globe seek new ways to safely hold public events.
A similar two-day experiment took place in the Netherlands in March with around 1,500 people.