Safe use of PHI6 IN the experimental studies

Surrogate viruses theoretically provide an opportunity to study the viral spread in an indoor environment, a highly needed understanding during the pandemic, in a safe manner to humans and the environment. However, the safety of surrogate viruses for humans as an aerosol at concentrations has not been established. In this study, Phi6 surrogate was aerosolized at concentration (Particulate matter(2.5): similar to 1018 mu g m(-3)) in the studied indoor space. Participants were closely followed for any symptoms. We measured the bacterial endotoxin concentration the virus solution used for aerosolization as well as the concentration in the room air containing the aerosolized viruses. In addition, we measured how the bacterial endotoxin concentration the sample was affected by different traditional virus purification procedures. Despite the puri-fication, bacterial endotoxin concentration of the Phi6 was high (350 EU/ml in solution used aerosols) with both (two) purification protocols. Bacterial endotoxins were also detected aerosolized form, but below the occupational exposure limit of 90 EU/m(3). Despite these concerns, no symptoms were observed in exposed humans when they were using personal protective equipment. In the future, purification protocols should be developed to reduce associated terial endotoxin levels in enveloped bacterial virus specimens to ensure even safer research use surrogate viruses.