What is the efficacy of standard face masks compared to respirator masks in preventing COVID-type respiratory illnesses in primary care staff?

Trish Greenhalgh and Xin Hui Chan, University of Oxford Kamlesh Khunti, University of Leicester Quentin Durand-Moreau and Sebastian Straube, University … Continue reading What is the efficacy of standard face masks compared to respirator masks in preventing COVID-type respiratory illnesses in primary care staff?