Music festivals, not guilty. Catalan epidemiologist Oriol Mitjà has spoken out to refute the importance of the holding of major music festivals in the rapid spread of the Delta-based fifth wave of Covid-19 in Catalonia. The contribution of the three large musical gatherings held in early July - Cruïlla, Vida and Canet Rock - was "insignificant" in the increase in infections this summer, he pointed out on social media. In fact, the testing carried out prior to festivals even acted to prevent some spread that would have otherwise occurred, and the real problem was the lack of restrictions in other areas.
After the Catalan health authorities announced on Wednesday that over 2,000 people were infected at these large events, Mitjà underlined the erroneous nature of that figure, since only around 800 of these cases can be attributed to the concerts. "The risk attributable to festivals is the difference between the incidence among attendees and that among non-attendees,” he wrote on Twitter.
Thus, if in the period between July 1st and July 24th, 140,000 cases were diagnosed in Catalonia, "the contribution of 800 cases is negligible." And he adds that "the number of new cases is small is not only due to the positive effect of the [antigen testing] carried out, but also to the fact that 50,000 attendees represent only a small part of the population."
The Catalan health ministry's alleged "error" in the calculations arises from a ‘big weakness’ of the study. It turns out that the comparison of people who went to the festivals with a control group who didn't is matched by sex and age, but does not take into account that those who did attend the musical events will tend to have a higher predisposition to attend other "risky" events. “That is, a young person who goes to music festivals is also more likely to go out for dinner,” Mitjà sums up.
To top it off, the epidemiologist notes that detection of 500 positive cases among would-be festivals goers (through antigen tests) prevented some 2,000 infections which would have taken place through possibly-unknowing virus propagation from people whose infection was, in fact, detected. On the other hand, the 800 cases among the non-concert attendees did generate secondary infections, so "almost as many cases were prevented as those that were caused."
Thus, he concludes that "the absolute number of cases was so small that it is acceptable to hold festivals, from the point of view of infection control, if the epidemiological situation is good."
The study presented by the CatSalut health service yesterday showed that there were 842 more infections than expected among those attending the Vida, Cruïlla and Canet Rock festivals. The number of 1,437 was expected, but in reality there were 2,279, almost 60% more. Based on this data, the public health secretary, Carmen Cabezas, said that the festivals did contribute to the spread of the virus during the fifth wave, while she avoided classing them as "superspreader" events.
Catalonia's minister of health, Josep Maria Argimon, had earlier acknowledged that errors had been made in the holding of the festivals, although he did not at that point know the results of the studies. This was a standpoint that Oriol Mitjà praised: "It is so good that he recognizes mistakes." Mistakes, however, that seem to have more to do with the lack of restrictions in other areas than with the celebration of the big summer concerts themselves, according to the epidemiologist. It should be remembered that the first significant measures against the expansion of the fifth wave in Catalonia came in mid-July, with the curfew for municipalities with high Covid incidence as the most significant restriction.
Main image: Audience members at the Vida festival, in early July / ACN