Late Breaking Abstract - Air and surface contamination with SARS-CoV-2 in rooms of infected nursing home residents: the Netherlands

Transmission routes of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) are not fully understood. Environmental contamination following an infection has been hypothesized as a risk factor for subsequent infection. The aim was to identify whether environmental contamination occurs in rooms of nursing home residents tested positive for SARS-CoV-2 to gain insight in potential transmission routes. Air samples were collected using three active air sampling techniques and settling dust was collected passively using Electrostatic Dust fall Collectors (EDC). Oropharyngeal swabs (OS) of the residents and dry surface swabs were collected. RNA was detected using RT-qPCR (cobas® 6800/8800 Systems (Roche Diagnostics)), targeting the RdRP-gene and E-gene. A selection of samples with Ct value <35 was cultured. In total, 378 environmental samples were collected in 13 nursing home residencies. In the rooms of 10 residents with positive OS, 92 of 174 collected samples were positive (52.9%)(Ct > 29,5), substantially more than in the rooms of residents with negative OS (1/28; 3.6%). The prevalence of positive samples was 64.3% in passive air samples (9/14) and 47.4% in active air samples (37/78). Both high-touch and low-touch surfaces in rooms of residents with positive OS contained SARS-CoV-2 (46/98; 46.9%). Three OS and one active air sample showed replication of virus (4/44). SARS-CoV-2 RNA was detected in air and surfaces surrounding SARS-CoV-2 infected nursing home residents suggesting substantial environmental contamination. Moreover, SARS-CoV-2 was cultured from one air sample, indicating that airborne particles containing SARS-CoV-2 may be infectious.