No covid infections at the experimental concert at Sala Apolo

BarcelonaEven the authors of the study did not expect this result. None of the 463 people who attended the concert three weeks ago at the Sala Apolo in Barcelona were infected with covid-19. This experimental concert wanted to check whether the audience contracted the virus and the answer was no, if the safety measures applied that day were complied with: wearing FPP2 masks that could only be removed for drinking in the bar - located in a different room - or for smoking outside, controls to avoid crowding in the queues to get in and out or to go to the toilet and hydroalcoholic gel dispensers. "It is safe to do this type of activity if it is repeated under the same conditions", said Dr Josep Maria Llibre, researcher on the study together with Dr Boris Revollo.

About 1,000 people attended the experimental concert on 12 December: 463 entered the Sala Apolo and 496 more were in the control group. They were given an antigen test, which after a few minutes had to be negative in order to continue with the research, and a PCR. The people in the control group did not attend the concert, but all the participants were able to live a normal life for the next eight days, following the restrictions by covid-19 that apply to the rest of the population. After this period, they were given a second PCR test. The result was that none of the 463 people attending the concert had been infected and that two of the 496 people in the control group had been: one had already been diagnosed three days after the concert and the other found out thanks to the test done as part of the study.

The only difference between the concert attendees and the control group is that the former had gone to "a mass event". "The control group is an identical group not exposed to the activity we are evaluating," explained Llibre. This has allowed them to conclude that although the audience could dance without keeping social distance, sing and drink at the bar, there were no infections. As to whether the study can be extrapolated to indoor spaces where people are sitting at a distance or outdoors, the doctor considered that the risk would be "lower" but added that "one has to be cautious". In fact, he warned that people cannot go out to party without control because the study has analysed a specific activity with a limited capacity, lower than Sala Apolo's maximum capacity. He also recalled that children, teenagers, the elderly and people with pathologies or in contact with people at risk were excluded.

Better an antigen test than a PCR

The study also served to establish that antigen tests are better than PCR for filtering the public. The reason is that, apart from the fact that the PCR result was not obtained until the following day, three people whose PCR test came back negative tested positive in the antigen test. Llibre has attributed the positive result to "a very low viral load, with no risk of transmission", but that caused this result. The three cases were an attendee at the concert, a member of the control group and a Sala Apolo worker - both tests were also carried out on all staff at the venue. Regarding the difference in the number of people between the audience -463- and the control group -496-, the doctor explained that about thirty of those who had to enter the concert decided not to in the end. He also acknowledged that seven of the audience did not undergo the second PCR but did not present any symptoms.

Llibre, who pointed out that the audience was inside the Sala Apolo for an average of 2 hours and 40 minutes, questioned whether the concerts should be labelledas "high risk" activities because of covid-19. This means that the number of tickets has had to be reduced and events cancelled. Dr Revollo added that those attending were "at the maximum stress level of exposure to the coronavirus". The researchers have encouraged to be aware of similar experiments in other countries to be able to influence the restrictions that apply. The study has been organised by the Fight Against AIDS Foundation, the Germans Trias i Pujol University Hospital and Primavera Sound Music Festival, which financed it.