The role of environmental transmission of SARS-CoV-2 remains unclear. Particularly the close contact of persons living together or cohabitating in domestic quarantine could result in high risk for exposure to the virus within the households. Therefore, the aim of this study was to investigate the whereabouts of the virus and whether useful precautions to prevent the dissemination can be given. 21 households under quarantine conditions were randomly selected for this study. All persons living in each household were recorded in terms of age, sex and time of household quarantine. Throat swabs for analysis were obtained from all adult individuals and most of the children. Air, wastewater samples and surface swabs (commodities) were obtained and analysed by RT- PCR. Positive swabs were cultivated to analyse for viral infectivity. 26 of all 43 tested adults (60.47 %) tested positive by RT-PCR. All 15 air samples were PCR- negative. 10 of 66 wastewater samples were positive for SARS-CoV-2 (15.15 %) as well as 4 of 119 object samples (3.36 %). No statistically significant correlation between PCR-positive environmental samples and the extent of infection spread inside the household could be observed. No infectious virus could be isolated under cell culture conditions. As we cannot rule out transmission through surfaces, hygienic behavioural measures are important in the households of SARS-CoV-2 infected individuals to avoid potential transmission through surfaces. The role of the domestic environment, in particular the wastewater load in washbasins and showers, in the transmission of SARS CoV-2 should be further clarified. Highlights: With public “shut downs” due to SARS-CoV-2, domestic infection is a main possible route of transmission. All analysed air samples were tested negative for SARS-CoV-2. 15.15 % of all wastewater samples (washbasin, showers and toilets) were tested positive. Only 3.36 % of all object samples were tested positive: one remote control, two metallic door knobs and one wooden stove overlay. This study supports the hypothesis that indirect environmental transmission may only play a minor role, which needs clarifications in further studies.

The role of environmental transmission of SARS-CoV-2 remains unclear. Thus, the aim of this study was to investigate whether viral contamination of air, wastewater, and surfaces in quarantined households result in a higher risk for exposed persons. For this study, a source population of 21 households under quarantine conditions with at least one person who tested positive for SARS-CoV-2 RNA were randomly selected from a community in North Rhine-Westphalia in March 2020. All individuals living in these households participated in this study and provided throat swabs for analysis. Air and wastewater samples and surface swabs were obtained from each household and analysed using qRT-PCR. Positive swabs were further cultured to analyse for viral infectivity. Out of all the 43 tested adults, 26 (60.47%) tested positive using qRT-PCR. All 15 air samples were qRT-PCR-negative. In total, 10 out of 66 wastewater samples were positive for SARS-CoV-2 (15.15%) and 4 out of 119 surface samples (3.36%). No statistically significant correlation between qRT-PCR-positive environmental samples and the extent of the spread of infection between household members was observed. No infectious virus could be propagated under cell culture conditions. Taken together, our study demonstrates a low likelihood of transmission via surfaces. However, to definitively assess the importance of hygienic behavioural measures in the reduction of SARS-CoV-2 transmission, larger studies should be designed to determine the proportionate contribution of smear vs. droplet transmission.

SARS-CoV-2 infection has been characterized as an upper and lower respiratory tract infection with symptoms ranging from sore throat, cough, headache, and fatigue to a severe respiratory syndrome that requires intensive care [1-7]. Although a lower death rate has been recorded for SARS-CoV-2 in comparison to other recent coronavirus outbreaks, such as MERS or SARS, a compromised respiratory status on admission has been associated with fatal outcomes. Among the >1200 SARS-CoV-2-infected individuals in Germany to date, many of the diagnosed persons show mild symptoms to no clinical signs of infection. Here we describe the onset and characteristics of symptoms in a cluster outbreak after a carnival celebration in a small town in the state of North Rhine-Westphalia currently contributing 43% of the total number of infected individuals in Germany to date [8]. Among the nearly 500 individuals in domestic quarantine as ordered by the Local Health Authority at that time, we interviewed 41 randomly selected individuals with qPCR confirmed SARS-CoV-2 infection. Inclusion criteria for the survey participation were: residents, positive for SARS-CoV-2 in pharyngeal swabs, ≥18 years of age, and confirmed informed consent. Median age was 40 years (IQR: 31-53, range: 18-82) and 51% were female. All persons examined had attended a carnival festivity also attended by the SARS-CoV-2positive index patient. All persons who attended this carnival festivity were tested for SARS-CoV-2 by the local health authorities 10 days later. Among survey participants, onset of symptoms began 12 days (IQR: 11-13) after probable infection and a median of 6 distinct symptoms (IQR: 4-8) were described.