Innovations in research and development have rapidly resulted in vaccines, diagnostic tests, and therapeutics for the control of COVID-19. Translation of these innovations into policy and action has resulted in highly successful vaccination programmes in many countries. Programmes such as the COVAX facility are making efforts to ensure more equitable distribution of vaccines and medicines for survival of those who are severely ill.1WHOThe Access to COVID-19 Tools (ACT) Accelerator.https://www.who.int/initiatives/act-acceleratorDate: 2021Date accessed: May 13, 2021Google Scholar, 2WHOCOVAX: working for global equitable access to COVID-19 vaccines.https://www.who.int/initiatives/act-accelerator/covaxDate: 2020Date accessed: May 13, 2021Google Scholar However, the same is not true for diagnostic tests. Although molecular tests that detect SARS-CoV-2 RNA have been widely used for diagnosis of acute infection since early in the pandemic, the uptake of antigen rapid diagnostic tests (Ag-RDTs) has been slow. Although less sensitive than molecular tests, Ag-RDTs are easy to perform, can yield a result in 15–20 min, and are less costly than molecular tests. Modelling studies showed that for screening, test sensitivity is secondary to frequency of testing and rapid time to result to prevent delays in breaking the chain of transmission through isolation and contact tracing.3Larremore DB Wilder B Lester E et al.Test sensitivity is secondary to frequency and turnaround time for COVID-19 screening.Sci Adv. 2021; 7eabd5393Crossref PubMed Scopus (366) Google Scholar, 4Mina MJ Parker R Larremore DB Rethinking COVID-19 test sensitivity–a strategy for containment.N Eng J Med. 2020; 383: e120Crossref PubMed Scopus (387) Google Scholar Evidence of the effectiveness of using Ag-RDTs in combination with prevention strategies, such as adequate ventilation, mandatory wearing of face masks, handwashing, and physical distancing, can be easily monitored and optimised for schools and college campuses, because they involve a fixed cohort of individuals gathering daily within the same facilities.5US Centers for Disease Control and PreventionInterim Guidance for SARS-CoV-2 testing and screening at institutions of higher education (IHEs).https://www.cdc.gov/coronavirus/2019-ncov/community/colleges-universities/ihe-testing.htmlDate: 2021Date accessed: May 8, 2021Google Scholar The Africa Centres for Disease Control and Prevention and the US Centers for Disease Control and Prevention have issued guidance on the use of antigen testing to ensure a safe environment in non-health care workplaces.6US Centers for Disease Control and PreventionAntigen testing for screening in non-healthcare workplaces: a tool to prevent the spread of COVID-19.https://www.cdc.gov/coronavirus/2019-ncov/community/workplaces-businesses/antigen-testing.htmlDate: 2021Date accessed: May 8, 2021Google Scholar, 7Africa Centres for Disease Control and PreventionInterim guidance on the use of rapid antigen tests for COVID-19 response.https://africacdc.org/download/interim-guidance-on-the-use-of-rapid-antigen-tests-for-covid-19-response/Date: 2020Date accessed: May 8, 2021Google Scholar However, designing and monitoring effectiveness of screening and preventive measures at one-time events that attract participants from diverse risk settings can be challenging. In this issue of The Lancet Infectious Diseases, Boris Revollo and colleagues8Revollo B Blanco I Soler P et al.Same-day SARS-CoV-2 antigen test screening in an indoor mass-gathering live music event: a randomised controlled trial.Lancet Inf Dis. 2021; (online May 27.)https://doi.org/10.1016/S1473-3099(21)00268-1Summary Full Text Full Text PDF PubMed Scopus (41) Google Scholar report on same-day SARS-CoV-2 rapid antigen test screening of 465 participants at an indoor music event in Sala Apolo, Barcelona, Spain, where at the time COVID-19 prevalence was estimated at 220·7 cases per 100 000 inhabitants. In their randomised clinical trial of screening immediately before and 8 days after the event, 1047 people were screened and all had a negative result. 523 people were randomly assigned to the experimental group to attend the music event where N95 face masks were compulsory, ventilation was adequate, and participants were permitted to sing and dance with the music. 524 participants were randomly assigned to the control group and were not permitted to attend the event. The study showed that the risk of infection was no higher among those attending the event than those who lived in the same community and did not attend. The Bayesian estimate for the incidence between the experimental and control groups was –0·15% (95% CI –0·72 to 0·44). By using viral culture and molecular testing in addition to Ag-RDT testing they found that specimens that were RNA-positive but Ag-RDT-negative were also culture negative, providing confidence in screening with an Ag-RDT. 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. The introduction of Ag-RDTs has been further complicated by conflicting reports of the sensitivity and specificity of Ag-RDTs in different study settings due to the lack of an international standard and the proportion of specimens of high and low viral loads used in different evaluation panels. For policy makers, additional concerns exist regarding false positive and negative test results.9Peeling RW Olliaro PL Boeras DI Fongwen N Scaling up COVD-19 rapid antigen tests: promises and challenges.Lancet Infect Dis. 2021; (published online Feb 23.)https://doi.org/10.1016/S1473-3099(21)00048-7Summary Full Text Full Text PDF Scopus (147) Google Scholar Singapore has provided guidance on the use of Ag-RDTs for pre-event testing for sports events, weddings, funerals, gatherings for worship, and opening of cinemas, museums, and tours but few countries have used these tests to their full advantage.10Singapore Ministry of HealthPre-event testing (PET).https://www.moh.gov.sg/covid-19/petDate: 2021Date accessed: May 8, 2021Google Scholar Well-designed, meticulously conducted, and comprehensively analysed studies that accompany innovations for the use of diagnostic tests for COVID-19 are urgently required. Publication of outcomes in peer-reviewed journals can provide the evidence needed to accelerate the resumption of a more normal life and the accompanying economic recovery and realise the full potential of the many diagnostic tests that research and development has produced. We declare no competing interests. Same-day SARS-CoV-2 antigen test screening in an indoor mass-gathering live music event: a randomised controlled trialOur study provides preliminary evidence on the safety of indoor mass-gathering events during a COVID-19 outbreak under a comprehensive preventive intervention. The data could help restart cultural activities halted during COVID-19, which might have important sociocultural and economic implications. Full-Text PDF