Assessing SARS-CoV-2 Prevalence in Austria with Sample Surveys in 2020 - A Report

Abstract

Since the beginning of the SARS-CoV-2 pandemic a main metric is the amount of infected people at any given time. We present a valid assessment of the population acutely infected by SARS-CoV-2 in Austria at three distinct points in time: April, May and November 2020. The population of these sample surveys includes people aged 16 or older living in private households.Participants were tested with PCR (polymerase chain reaction) tests using nose-throat swabs. Based on these tests, it is assumed that the number of acute SARS-CoV-2 infections was below 11,000 individuals, or 0.15\% of the target population, in April, below 6,000, in May and below 265,000 in November (i.e. the upper limit of the 95\% confidence interval). In November a comparison with the Austrian Epidemiological Reporting System reveals that more than estimated 50\% of acute infections remain undetected by the official reporting obligations.