Assessment of the National Test Strategy on the Development of the COVID-19 Pandemic in Denmark

Abstract

During the COVID-19 pandemic, Denmark has pursued a mass testing strategy culminating in the testing of 12.167 individuals per 100,000 inhabitants per day during the spring of 2021. The strategy included free access to COVID-19 testing, and since 2021, compulsory documentation for negative tests or vaccination has been required for access to workplace, educational institutions, restaurants, and many other places. Testing and subsequent isolation if testing was positive were voluntary. The present study provides an analysis of whether testing frequency in Denmark showed any correlation to hospitalizations throughout the relevant stages of the pandemic. Mass testing was found not to correlate significantly with the number of hospitalizations during the pandemic. Interestingly, during the highest level of testing in spring 2021 the fraction of positive tests increased slightly; thus, the Danish mass testing strategy, at its best, failed to reduce the prevalence of COVID-19. Furthermore, the relationship between positives in antigen testing and in rt-PCR testing indicated that many patients were not tested early in their infection when the risk of transmission was at the highest. In conclusion, the Danish mass testing strategy for COVID-19 does not appear to have a detectable correlation to the number of hospitalizations due to COVID-19.

Results from Canton Grisons of Switzerland suggest repetitive testing reduces SARS-CoV-2 incidence (February–March 2021)

“…To date, population-based mass testing has been carried out and documented in countries such as the UK, Denmark, China, South Korea, Austria, Luxembourg, and Slovakia, that have mostly used rapid antigen tests [8][9][10][11][12][13][14] . In Slovakia, a few rounds of population-wide mass testing were estimated to yield a 70% decline of infection prevalence 10,11 .…”

Effectiveness of rapid antigen testing for screening of asymptomatic individuals to limit the transmission of SARS‐CoV‐2: A rapid review

“…A recently published study found that the intensive Danish mass testing strategy (using both RT‐PCR and RADTs) did not significantly reduce the prevalence of SARS‐CoV‐2 and had no impact on the number of hospitalisations. 52 The authors suggested that the mass testing may have increased risk behaviours of those tested, or that antigen testing may have occurred too late in the course of the infection to prevent onward transmission, hence contributing to the spread of infection in the community. It is important to note that while RADTs can reliably detect some of those most likely to be infectious at the time of testing, transmission can still occur in those with high cycle threshold ( C t ) values (indicative of low viral load) with no accepted cut‐off of C t values at which the risk of transmission is eliminated.…”

“…A recently published study found that the intensive Danish mass testing strategy (using both RT-PCR and RADTs) did not significantly reduce the prevalence of SARS-CoV-2 and had no impact on the number of hospitalisations. 52 The authors suggested that the mass testing may have increased risk behaviours of those tested, or that 53 This point is illustrated in the study by Moreno et al, where screening missed some infectious cases despite the implementation of mandatory directly observed daily antigen testing. 35 Though RADTs may be relatively inexpensive and easy to administer at an individual level, 16 real-world evidence from included studies highlights the significant resource, implementation and social issues associated with using RADTs at scale.…”

“…A recently published study found that the intensive Danish mass testing strategy (using both RT‐PCR and RADTs) did not significantly reduce the prevalence of SARS‐CoV‐2 and had no impact on the number of hospitalisations 52 . The authors suggested that the mass testing may have increased risk behaviours of those tested, or that antigen testing may have occurred too late in the course of the infection to prevent onward transmission, hence contributing to the spread of infection in the community.…”

Factors associated with the formation of SARS-CoV-2 case-clusters in Danish schools: a nationwide register-based observational study

“…In addition, the Danish response to the COVID-19 pandemic included mass testing [ 12 ]. Denmark massively scaled up its testing capacity and ensured that every citizen had the right to be tested free of charge and independent of medical referral [ 13 , 14 ]. Also in schools, testing capacities were increased and voluntary screening was implemented.…”