Characterization of Rhamnolipids for the Inactivation of Enveloped Viruses

In the face of new emerging respiratory viruses, such as SARS-CoV2, vaccines, and drug therapies are not immediately available to curb the spread of the infection. Non-pharmaceutical interventions, such as mask-wearing and social distance, can slow the transmission. However, both mask and social distance are not 100% effective at preventing the spread of respiratory viruses, such as SARS-CoV2 and influenza viruses. There is an urgent need to develop an intervention that could reduce the spread of respiratory viruses. Rhamnolipids are environmentally friendly and biologically safe surfactants that can kill enveloped viruses. Two rhamnolipid products, 222A and 222B, were investigated in this study to determine their ability to inactivate two enveloped viruses, bovine coronavirus and herpes simplex virus 1. We found that 222B at 0.005%, which has no toxicity to cells, can inactivate 105 PFU/ml enveloped viruses in 3-5 min. Moreover, 50-100µl of 222B at 0.005% on 1 cm2 mask fabrics can inactivate ~ 103 PFU /10 µl in 3-5 min. These results suggest that 222B can be coated on masks to prevent or reduce the spread of enveloped viruses.