• Study conducted in Barcelona, Spain, is the first randomised controlled trial to assess risk of COVID-19 transmission at an indoor live music concert with comprehensive safety measures.
  • All 465 event attendees were screened using lateral flow tests before entry, wore masks throughout, and adhered to crowd control in the well-ventilated venue. They were compared with 495 participants who were randomly assigned to go home after taking a lateral flow test and did not attend the concert.
  • None of the attendees tested positive for SARS-CoV-2 infection by PCR test eight days after the event, compared with two people in the control group.
  • Findings offer a step towards restarting music and other cultural activities that were halted during the COVID-19 pandemic, but the authors stress the strict conditions in their study may be difficult to reproduce across many venues, or larger events with more attendees, and that more research is needed to understand mass gatherings in different contexts of the COVID-19 pandemic (eg, local incidence, local seroprevalence, and vaccination rollout).

The first randomised controlled trial to assess the impact of comprehensive COVID-19 safety measures at an indoor live music concert reports zero cases of virus transmission, according to a study published in The Lancet Infectious Diseases journal.

Safety precautions included same-day screening of attendees using lateral flow COVID-19 tests before entry, mandatory N95 mask wearing, enhanced ventilation, and crowd control. Participants were allowed to sing and dance in the concert hall room and there was no recommendation for physical distancing.

The study was conducted in Barcelona, Spain, on December 12, 2020, when the prevalence of SARS-CoV-2 infections in the region was low to intermediate (221 cases per 100,000 people), so the authors note that the number of new SARS-CoV-2 infections resulting from the event would have been expected to be low. At the time, local travel restrictions were in place, indoor meetings were limited to six people, and COVID-19 vaccines were not yet available.

The study’s lead author, Dr Josep Llibre, of the Germans Trias i Pujol University Hospital, Spain, said: “Our study provides early evidence that indoor music events can take place without raising the risk of SARS-CoV-2 transmission when comprehensive safety measures are in place, but it is important that our findings are considered in light of the situation in Spain at the time – when cases were not high and many restrictions were in place. As a result, our study does not necessarily mean that all mass events are safe.” [1]

He adds: “The conditions of the pandemic are constantly shifting. Widespread vaccination campaigns, changes in local incidence and the emergence of SARS-CoV-2 variants with higher transmissibility could all impact the interventions we tested, so we need more studies including larger numbers of people that explore different scenarios and policies that take into consideration the local context.” [1]

Boris Revollo, of the Germans Trias i Pujol University Hospital, Spain, one of the study’s co-authors, said: “Mass gatherings are associated with a high risk of spreading the SARS-CoV-2 virus and the cancellation of large events has played an important role in bringing the COVID-19 pandemic under control. However, these cancellations have resulted in substantial economic losses, estimated in the region of €5.5 billion in Spain alone. As societies look toward the possibility of safely resuming cultural activities, lateral flow tests, which can deliver results within 30 minutes and be taken on site, have been proposed as a means of screening people on entry to enable large events to take place.”

In this study, researchers carried out a controlled experiment to see if mass testing on entry using lateral flow tests alongside other preventive measures aimed at blocking SARS-CoV-2 transmission, could successfully be done, and if it could create a safe environment for a large indoor event.

Around 1,000 people aged between 18 and 59 years were recruited to take part. People were excluded if they had tested positive for COVID-19 or been in contact with a positive COVID-19 case in the previous two weeks, had pre-existing health conditions that are known risk factors for severe COVID-19 disease, or were living with older people at the time of the study.

All participants tested negative on a lateral flow test conducted by a healthcare professional. Around half were randomly allocated to attend the event (465), with the other half asked to return home to their regular lives (495). The same swab samples from each participant were sent to a laboratory for confirmatory COVID-19 testing. All participants, including those who did not attend the event, were visited by a healthcare professional eight days after the event for collection of a second swab from the back of the nose and throat for repeat COVID-19 testing.

The indoor event took place at the Sala Apolo venue in Barcelona, which usually has an event capacity of around 900 people. In addition to testing, all attendees had their temperature monitored before being allowed entry to the venue and were given an N95 face mask, which had to be worn at all times inside the venue. Hand sanitiser was provided at multiple points, the venue was well ventilated (all access and exit doors remained open throughout to allow fresh air to circulate) and the temperature was controlled so that attendees could comfortably wear their masks, and the cloakroom was closed to avoid queueing.

The event itself lasted five hours and attendees spent an average of two hours and 40 minutes inside the venue. There were two DJ performances and two live music acts. Drinks, including alcohol, were served in a separate bar room and there was a smoking area outside with controlled capacity and physical distancing.

Everyone who took part in the study was required to install two smartphone apps – one contact tracing app to capture close contacts of people who may have become infected during the concert, and a separate app to receive confidential test results. Participants also used this second app to complete health questionnaires before and 10 days after the event, as well as a satisfaction survey for those who attended the event.

None of the people who attended the event tested positive for COVID-19 eight days after the event, compared with two people from the control group. The two individuals who tested positive did so on both lateral flow and were confirmed in PCR tests. The number of cases in the control group is low and in line with the epidemiological situation in Barcelona at the time of the study. Overall, the findings show there was no increased transmission of SARS-CoV-2 associated with event attendance.

In a post event questionnaire, most attendees reported feeling able to behave normally despite the safety precautions. They reported an average satisfaction score of 8.6 out of 10 when asked to rate how well they had been able to enjoy the performance. When asked how willing they would be to attend another event with the same safety procedures, the average score was more than nine out of 10 (where 10 is most willing).

Some 28 people tested positive on the confirmatory test at baseline (which used the same swabs as the first lateral flow test – 13 people in the event group and 15 in the control). Further lab tests confirmed none of these people were infected with live virus, indicating they were unlikely to be able to transmit SARS-CoV-2. All 28 of those with a positive result had previously been diagnosed with COVID-19 around seven weeks before the study took place.

Cristina Casañ, one of the study’s co-authors, from the Catalan Health Institute, Spain, said: “In our study, lateral flow tests were around 99.9% accurate at detecting negative results, as confirmed by PCR testing, and their short-turnaround time may make them more appropriate for screening at mass-gathering events. Other tests that work by detecting the virus’ genetic material can also detect residual virus even when not transmissible. These tests could result in positive results that would prevent people who aren’t infectious from attending events.” [1]

The authors note that the comprehensive safety measures in place during their event may be cost-prohibitive for some venues. Additionally, testing thousands of people within a few hours before a mass gathering event poses logistical challenges. Smartphone apps to deliver results to attendees can help with this, while maintaining users’ privacy. However, they highlight that the public health implications of identifying and isolating COVID-19-infected individuals in an age group that often remains undetected should also be considered when evaluating the costs and benefits of their approach.

Another potential limitation of the study is that participants may have modified their behaviour during the event due to their awareness of being observed. However, in the post-event questionnaire, all participants reported behaving normally during the event and did not feel under the scrutiny of security controls.

Writing in a linked Comment, Professor Rosanna Peeling, of the London School of Hygiene and Tropical Medicine, who was not involved in the study, said: “This study is an important reminder of the need to carry out well-designed studies as innovation in the use of diagnostic tests continues. These studies generate additional questions to form hypotheses for further model outputs. For example, would triple-layered masks have been sufficient? How does rapid antigen testing at entry compare with molecular screening within 72 h of entry? Does screening create bottlenecks with an increased risk of transmission among those not yet tested? Which study design would be required when attendees are not all from the same community but attending international events such as the Olympic and Paralympic Games? And the question of concern for all is whether existing RDTs are able to detect COVID-19 variants of concern and the role of vaccination.”

NOTES TO EDITORS

The study was funded by concert organisers, Primavera Sound Group (Spain), and the #Yomecorono Initiative (Spain). It was carried out by researchers from the Foundation for Fighting AIDS, Infectious Diseases and Promoting Health and Science (Spain), Germans Trias i Pujol University Hospital (Spain), the Catalan Health Institute (Spain), Primavera Sound Group, Germans Trias i Pujol Research Institute (Spain), the Polytechnic University of Catalonia – BarcelonaTech (Spain), Bellvitge Biomedical Research Institute (Spain), the University of Vic – Central University of Catalonia (Spain) and the Autonomous University of Barcelona (Spain).

The labels have been added to this press release as part of a project run by the Academy of Medical Sciences seeking to improve the communication of evidence. For more information, please see: http://www.sciencemediacentre.org/wp-content/uploads/2018/01/AMS-press-release-labelling-system-GUIDANCE.pdf if you have any questions or feedback, please contact The Lancet press office pressoffice@lancet.com

[1] Quote direct from author and cannot be found in the text of the Article.

  • Study conducted in Barcelona, Spain, is the first randomised controlled trial to assess risk of COVID-19 transmission at an indoor live music concert with comprehensive safety measures.
  • All 465 event attendees were screened using lateral flow tests before entry, wore masks throughout, and adhered to crowd control in the well-ventilated venue. They were compared with 495 participants who were randomly assigned to go home after taking a lateral flow test and did not attend the concert.
  • None of the attendees tested positive for SARS-CoV-2 infection by PCR test eight days after the event, compared with two people in the control group.
  • Findings offer a step towards restarting music and other cultural activities that were halted during the COVID-19 pandemic, but the authors stress the strict conditions in their study may be difficult to reproduce across many venues, or larger events with more attendees, and that more research is needed to understand mass gatherings in different contexts of the COVID-19 pandemic (eg, local incidence, local seroprevalence, and vaccination rollout).

The first randomised controlled trial to assess the impact of comprehensive COVID-19 safety measures at an indoor live music concert reports zero cases of virus transmission, according to a study published in The Lancet Infectious Diseases journal.

Safety precautions included same-day screening of attendees using lateral flow COVID-19 tests before entry, mandatory N95 mask wearing, enhanced ventilation, and crowd control. Participants were allowed to sing and dance in the concert hall room and there was no recommendation for physical distancing.

The study was conducted in Barcelona, Spain, on December 12, 2020, when the prevalence of SARS-CoV-2 infections in the region was low to intermediate (221 cases per 100,000 people), so the authors note that the number of new SARS-CoV-2 infections resulting from the event would have been expected to be low. At the time, local travel restrictions were in place, indoor meetings were limited to six people, and COVID-19 vaccines were not yet available.

The study’s lead author, Dr Josep Llibre, of the Germans Trias i Pujol University Hospital, Spain, said: “Our study provides early evidence that indoor music events can take place without raising the risk of SARS-CoV-2 transmission when comprehensive safety measures are in place, but it is important that our findings are considered in light of the situation in Spain at the time – when cases were not high and many restrictions were in place. As a result, our study does not necessarily mean that all mass events are safe.” [1]

He adds: “The conditions of the pandemic are constantly shifting. Widespread vaccination campaigns, changes in local incidence and the emergence of SARS-CoV-2 variants with higher transmissibility could all impact the interventions we tested, so we need more studies including larger numbers of people that explore different scenarios and policies that take into consideration the local context.” [1]

Boris Revollo, of the Germans Trias i Pujol University Hospital, Spain, one of the study’s co-authors, said: “Mass gatherings are associated with a high risk of spreading the SARS-CoV-2 virus and the cancellation of large events has played an important role in bringing the COVID-19 pandemic under control. However, these cancellations have resulted in substantial economic losses, estimated in the region of €5.5 billion in Spain alone. As societies look toward the possibility of safely resuming cultural activities, lateral flow tests, which can deliver results within 30 minutes and be taken on site, have been proposed as a means of screening people on entry to enable large events to take place.”

In this study, researchers carried out a controlled experiment to see if mass testing on entry using lateral flow tests alongside other preventive measures aimed at blocking SARS-CoV-2 transmission, could successfully be done, and if it could create a safe environment for a large indoor event.

Around 1,000 people aged between 18 and 59 years were recruited to take part. People were excluded if they had tested positive for COVID-19 or been in contact with a positive COVID-19 case in the previous two weeks, had pre-existing health conditions that are known risk factors for severe COVID-19 disease, or were living with older people at the time of the study.

All participants tested negative on a lateral flow test conducted by a healthcare professional. Around half were randomly allocated to attend the event (465), with the other half asked to return home to their regular lives (495). The same swab samples from each participant were sent to a laboratory for confirmatory COVID-19 testing. All participants, including those who did not attend the event, were visited by a healthcare professional eight days after the event for collection of a second swab from the back of the nose and throat for repeat COVID-19 testing.

The indoor event took place at the Sala Apolo venue in Barcelona, which usually has an event capacity of around 900 people. In addition to testing, all attendees had their temperature monitored before being allowed entry to the venue and were given an N95 face mask, which had to be worn at all times inside the venue. Hand sanitiser was provided at multiple points, the venue was well ventilated (all access and exit doors remained open throughout to allow fresh air to circulate) and the temperature was controlled so that attendees could comfortably wear their masks, and the cloakroom was closed to avoid queueing.

The event itself lasted five hours and attendees spent an average of two hours and 40 minutes inside the venue. There were two DJ performances and two live music acts. Drinks, including alcohol, were served in a separate bar room and there was a smoking area outside with controlled capacity and physical distancing.

Everyone who took part in the study was required to install two smartphone apps – one contact tracing app to capture close contacts of people who may have become infected during the concert, and a separate app to receive confidential test results. Participants also used this second app to complete health questionnaires before and 10 days after the event, as well as a satisfaction survey for those who attended the event.

None of the people who attended the event tested positive for COVID-19 eight days after the event, compared with two people from the control group. The two individuals who tested positive did so on both lateral flow and were confirmed in PCR tests. The number of cases in the control group is low and in line with the epidemiological situation in Barcelona at the time of the study. Overall, the findings show there was no increased transmission of SARS-CoV-2 associated with event attendance.

In a post event questionnaire, most attendees reported feeling able to behave normally despite the safety precautions. They reported an average satisfaction score of 8.6 out of 10 when asked to rate how well they had been able to enjoy the performance. When asked how willing they would be to attend another event with the same safety procedures, the average score was more than nine out of 10 (where 10 is most willing).

Some 28 people tested positive on the confirmatory test at baseline (which used the same swabs as the first lateral flow test – 13 people in the event group and 15 in the control). Further lab tests confirmed none of these people were infected with live virus, indicating they were unlikely to be able to transmit SARS-CoV-2. All 28 of those with a positive result had previously been diagnosed with COVID-19 around seven weeks before the study took place.

Cristina Casañ, one of the study’s co-authors, from the Catalan Health Institute, Spain, said: “In our study, lateral flow tests were around 99.9% accurate at detecting negative results, as confirmed by PCR testing, and their short-turnaround time may make them more appropriate for screening at mass-gathering events. Other tests that work by detecting the virus’ genetic material can also detect residual virus even when not transmissible. These tests could result in positive results that would prevent people who aren’t infectious from attending events.” [1]

The authors note that the comprehensive safety measures in place during their event may be cost-prohibitive for some venues. Additionally, testing thousands of people within a few hours before a mass gathering event poses logistical challenges. Smartphone apps to deliver results to attendees can help with this, while maintaining users’ privacy. However, they highlight that the public health implications of identifying and isolating COVID-19-infected individuals in an age group that often remains undetected should also be considered when evaluating the costs and benefits of their approach.

Another potential limitation of the study is that participants may have modified their behaviour during the event due to their awareness of being observed. However, in the post-event questionnaire, all participants reported behaving normally during the event and did not feel under the scrutiny of security controls.

Writing in a linked Comment, Professor Rosanna Peeling, of the London School of Hygiene and Tropical Medicine, who was not involved in the study, said: “This study is an important reminder of the need to carry out well-designed studies as innovation in the use of diagnostic tests continues. These studies generate additional questions to form hypotheses for further model outputs. For example, would triple-layered masks have been sufficient? How does rapid antigen testing at entry compare with molecular screening within 72 h of entry? Does screening create bottlenecks with an increased risk of transmission among those not yet tested? Which study design would be required when attendees are not all from the same community but attending international events such as the Olympic and Paralympic Games? And the question of concern for all is whether existing RDTs are able to detect COVID-19 variants of concern and the role of vaccination.”

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.