The coronavirus disease 2019 (COVID-19) outbreak, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged in Wuhan in December 2019 and has spread globally, representing a serious threat to public health. While waiting for highly effective treatments or the development of an effective vaccine, it is necessary to reactivate key economic activities that are related to leisure and culture in an environment that is safest for the participants.

The use of a rapid screening test for SARS-CoV-2 viral antigens with high sensitivity could be a useful tool to detect asymptomatic SARS-CoV-2 infected people, and thus be able to carry out events related to leisure in a safe environment.

The aim of this study is to make a mass screening of asymptomatic infection of an (i) experimental group (public attending a massive mass musical show) and (ii) a control group (they will not enter the event) prior to entering to the event.

Randomization 1: 1 by random blocks of the participants with a negative antigen test in the experimental group (attending the event) and the control group (they will not enter the event).

Control with a new Polymerase Chain Reaction (PCR) test 8 days after the event (D8) in the participants of both randomized groups Control of the appearance of symptoms through a questionnaire 10 days after the event (D10), in the participants of both groups with a negative result on day 8.

Validation of a rapid antigen detection test by comparison with the PCR technique.

The indoor activity will include an array of measures designed to reducing the contagion risk, including: mandatory wearing a mask during the event, restricted outdoor areas of bar and smoking, enhanced ventilation of the whole indoor area, and avoiding queues.

All subjects will have downloaded an app in their smart phones to help contact and place tracing during the event, to trace potential transmissions. This app will remain active for 8 days, until the last virologic control.

The inclusion criteria will allow only subjects with an age <60 years, without comorbidities, and who do not live with old adults in their homes, to further reduce the risk of potential complications and transmission to at risk individuals.

The coronavirus disease 2019 (COVID-19) outbreak, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged in Wuhan in December 2019 and has spread globally, representing a serious threat to public health. While 80% of patients are asymptomatic or have a mild illness, 20% develop a severe illness. The predominant symptoms include fever, cough, and myalgia. Mild disease can resolve without medical attention or it can progress to pneumonia and respiratory failure requiring hospitalization. Patients can rapidly progress to acute respiratory distress syndrome (ARDS) with multiple organ dysfunction and death.

The degree to which the virus is infectious during the incubation period is uncertain, but it has been shown that the pharynx reaches peak viral load before day 5, and this peak viral load is 1,000 times higher than in severe acute respiratory syndrome coronavirus (SARS-CoV). This active and high viral clearance from the pharynx at a time when symptoms are still mild makes the transmission of SARS-CoV-2 more efficient than that of SARS-CoV. Later in the disease, COVID-19 resembles SARS in terms of replication in the lower respiratory tract. The decrease in viral load appears to be slow, and there is no sudden shedding of the virus at the time of seroconversion. Seroconversion, at the beginning of week 2, has been observed to coincide with a slow but steady decrease in sputum viral load. Prolonged viral shedding in sputum is relevant not only for infection control in hospitals and discharge management, but also for asymptomatic people who can transmit the virus for longer periods after infection.

Although it is true that the majority of people infected by SARS-CoV-2 will have a benign course with few symptoms, approximately 20% will require hospitalization and 5% will present serious complications and admission to an intensive care unit, this is it translates into a saturation and collapse of health systems, with a high percentage of mortality in relation to it. Unprecedented confinement measures have been implemented that have been effective in containing the progression of the number of infections, but these have had a great social and economic impact, among others with a paralysis of most of the activities related to leisure (concerts , music festivals, theaters, etc.) that are an important component in the economy of most of the countries of the European community. While waiting for highly effective treatments or the development of an effective vaccine, it is necessary to reactivate key economic activities that are related to leisure and culture in an environment that is safest for the participants.

The use of a rapid screening test for SARS-CoV-2 viral antigens with high sensitivity could be a useful tool to detect asymptomatic SARS-CoV-2 infected people, and thus be able to carry out events related to leisure in a safe environment.

It is necessary to implement versatile circuits in which diagnoses with rapid tests can be carried out in the same place of the events in a massive way and to be able to communicate the results of the tests to the assistants at the same time, in order to do this screening of people that they give negative and carry out activities with them in a safe environment for all participants.

The aim of this study is to make a mass screening of asymptomatic infection of an (i) experimental group (public attending a massive mass musical show) and (ii) a control group (they will not enter the event) prior to entering to the event.

Randomization 1: 1 by random blocks of the participants with a negative antigen test in the experimental group (attending the event) and the control group (they will not enter the event).

Control with a new PCR test 8 days after the event (D8) in the participants of both randomized groups Control of the appearance of symptoms through a questionnaire 10 days after the event (D10), in the participants of both groups with a negative result on day 8.

Validation of a rapid antigen detection test by comparison with the PCR technique.

The indoor activity will include an array of measures designed to reducing the contagion risk, including: mandatory wearing a mask during the event, restricted outdoor areas of bar and smoking, enhanced ventilation of the whole indoor area, and avoiding queues.

All subjects will have downloaded an app in their smart phones to help contact and place tracing during the event, to trace potential transmissions. This app will remain active for 8 days, until the last virologic control.

The inclusion criteria will allow only subjects with an age <60 years, without comorbidities, and who do not live with old adults in their homes, to further reduce the risk of potential complications and transmission to at risk individuals.

Inclusion Criteria:

• Adults (age 18-59 years) with interest to attend the scheduled musical event who agree to participate in the study after signing the informed consent, including explicit acceptance of the measures implemented to reduce the risk of transmission of SARS-CoV-2.
• Negative antigen test performed up to 24 h before the event, in nasopharyngeal swab.

Exclusion Criteria:

• Hypertension
• Diabetes Mellitus.
• Ischemic heart disease.
• Any type of Cancer in active treatment.
• Chronic lung diseases such as chronic obstructive pulmonary disease (COPD) and asthma.
• Have a positive test for detection of SARS-CoV-2 by the rapid antigen test
• Who have a body temperature higher than 37.0º on the same day of the event
• Who have a confirmed diagnosis for SARS-CoV-2 in the two weeks prior to the event
• Report any symptoms suggestive of a SARS-CoV-2 infection in the 10 days prior to the study
• Who have been in contact with a person with a confirmed diagnosis of SARS-CoV-2 infection within two weeks prior to the event.
• Living with a person over 70 years of age (inclusive).