LAUSR

Background: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has emerged as an unprecedented global crisis challenging health systems. The dynamic nature of the pandemic warrants ongoing characterisation and assessment of outbreak settings to identify groups at greatest risk, to establish early measures to curb transmission. The current analysis aims to assess and characterise SARS-CoV-2 outbreaks in the state of Baden-Wuerttemberg. Methods: We analysed all mandatory notified (i.e. laboratory-confirmed) coronavirus disease (COVID-19) outbreaks from the state of Baden-Wuerttemberg in calendar weeks 18 to 49 (from April 27 to December 06, 2020). We used the following classification for settings: asylum and refugee accommodation, care homes, care facilities, day care child centers, hobby related, hospitality, hospitals, households, other, residence halls, schools, supported housing, training schools, transportation, treatment facilities, and workplace (occupational). We used R program version 3.6.3 for analysis. Results: In the current analysis, 3,219 outbreaks with 22,238 individuals were included. Around 48% of all outbreaks in this period were in household settings and hobby related activities. We observed an exponential increase in the number of notified outbreaks starting around the 41th week with N = 291 outbreaks reported in week 49. We observed an increase in hospitalisations, and mortality associated with COVID-19 outbreaks in care homes after the 40th week. Overall, 70% (500/715) of all deceased persons in outbreaks in the study period were in care homes compared to 4.2% in household settings (30/715). Conclusions: The increase in the number of outbreaks and in the number of cases per outbreak in high-risk settings, specifically in care homes after the 40th week highlights the imperative of controlling transmission in vulnerable populations.