Exploring Integrated Environmental Viral Surveillance of Indoor Environments: A comparison of surface and bioaerosol environmental sampling in hospital rooms with COVID-19 patients

The outbreak of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has dramatically transformed policies and practices surrounding public health. One such shift is the expanded emphasis on environmental surveillance for pathogens. Environmental surveillance methods have primarily relied upon wastewater and indoor surface testing, and despite substantial evidence that SARS-CoV-2 commonly travels through space in aerosols, there has been limited indoor air surveillance. This study investigated the effectiveness of integrated surveillance including an active air sampler, surface swabs and passive settling plates to detect SARS-CoV-2 in hospital rooms with COVID-19 patients and compared detection efficacy among sampling methods. The AerosolSense active air sampler was found to detect SARS-CoV-2 in 53.8% of all samples collected compared to 12.1% detection by passive air sampling and 14.8% detection by surface swabs. Approximately 69% of sampled rooms (22/32) returned a positive environmental sample of any type. Among positive rooms, ~32% had only active air samples that returned positive, while ~27% and ~9% had only one or more surface swabs or passive settling plates that returned a positive respectively, and ~32% had more than one sample type that returned a positive result. This study demonstrates the potential for the AerosolSense to detect SARS-CoV-2 RNA in real-world healthcare environments and suggests that integrated sampling that includes active air sampling is an important addition to environmental pathogen surveillance in support of public health.