Investigating the Dark Figure of COVID-19 Cases in Austria: Borrowing From the Decode Genetics Study in Iceland

Abstract

The number of undetected cases of SARS-CoV-2 infections is expected to be a multipleof the reported figures mainly due to the high ratio of asymptomatic infections and tolimited availability of trustworthy testing resources. Relying on the deCODE study inIceland, which offers large scale testing among the general population, we investigate themagnitude and uncertainty of the number of undetected cases COVID-19 cases in Austria.We formulate several scenarios relying on data on the number of COVID-19 cases whichhave been hospitalized, in intensive care, as well as on the number of deaths and positivetests in Iceland and Austria. We employ frequentist and Bayesian methods for estimatingthe dark figure in Austria based on the hypothesized scenarios and for accounting for theuncertainty surrounding this figure.Using data available on April 1, 2020, our study contains two main findings: First, wefind the estimated number of infections to be on average around 8.35 times higher thanthe recorded number of infections. Second, the width of the uncertainty bounds associatedwith this figure depends highly on the statistical method employed. At a 95% level, lowerbounds range from 3.96 to 6.83 and upper bounds range from 9.82 to 12.61. Overall, ourfindings confirm the need for systematic tests in the general population of Austria.

How many lives can be saved? A global view on the impact of testing, herd immunity and demographics on COVID-19 fatality rates

“…In Austria, which is a country that started testing at high proportions, the CFR value suggests that around than 25% of the infected individuals are tested. As a result, the total number of infected individuals is at least more than four times the total infected individuals tested, which coincides with the lower bound estimated by a recent study (25). We extend the analysis to the whole world, with results detailed in the supplementary materials (see Fig.…”

Reopening the Bavarian State Opera Safely: Hygiene Strategies and Incidence of COVID-19 in Artistic Staff During Theater Season 2020/2021

“…Interestingly, the incidence of SARS-CoV-2 positive cases in the investigated time period was lower in the Bavarian State Opera than in Bavaria and Germany, respectively. This is even more astounding since weekly up to 300 of 1,700 employees (17.6%) were tested at least once and thus testing frequency was much higher than that in overall Germany (maximum 0,5%) It is well known the real number of SARS-CoV-2 infections is up to 8.35 compared to the amount of tested people [39] and if the test frequency is elevated a higher incidence is expected. Over time, in 39 of 48 weeks, the estimated 7-day incidence per 100,000 employees of the Bavarian State Opera was lower than the respective 7-day incidence per 100,000 Bavarians, and in 23 weeks, no single case had been detected.…”

Prevalence of SARS-CoV-2 IgG antibodies in a large prospective cohort study of elite football players in Germany (May–June 2020): implications for a testing protocol in asymptomatic individuals and estimation of the rate of undetected cases

“…Estimations of number of undetected infections were rarely done so far. A study using data from Austria and Iceland found an almost similar factor of 8.35 [ 9 ], whereas a factor of 5 was determined in a hot spot area [ 8 ].…”