Article content A shortage of medical-grade mask at the start of the pandemic led authorities to treat COVID-19 as if it wasn’t an airborne contagion despite not fully knowing how the virus was spread, researchers involved in a national study have found. Without a complete understanding of how the deadly virus was being transmitted, health-care workers were wearing surgical masks – an inadequate respiratory protection – while treating those first COVID patients, University of Windsor researcher Jim Brophy said. We apologize, but this video has failed to load. Try refreshing your browser. Study looks at COVID-19's toll on health-care workers Back to video