> Live influenza virus was measurable from the air behind all surgical masks tested. The data indicate that a surgical mask will reduce exposure to aerosolised

> Live influenza virus was measurable from the air behind all surgical masks tested. The data indicate that a surgical mask will reduce exposure to aerosolised in- fectious influenza virus; reductions ranged from 1.1- to 55-fold (average 6-fold), depending on the design of the mask.