BARCELONA, Spain (AP) — Five thousand music lovers are set to attend a rock concert in Barcelona after passing a COVID-19 screening, to test its effectiveness in preventing outbreaks at large cultural events. The show on Saturday has the permission of Spanish health authorities. Concertgoers will undergo a antigen test hours before the concert. Those who test negative will be able to attend the indoor concert and mix freely, although face masks will be mandatory. The concert is an expanded version of a case study in December based on a concert for 500 people that organizers said showed no sign of contagion.