After the mask policy was implemented, a drop in infections was noticed after a few days The study also found that nurses have a higher chance of contracting the virus than other healthcare workers A new study found that the implementation of a universal mask policy early on in the Covid-19 pandemic was associated with reducing healthcare workers' risk of contracting the disease. The research published in the Journal of Occupational and Environmental Medicine investigated the effects of a universal facemask policy for healthcare workers (HCW) on the incidence of Covid-19. Establishing a mask policy The scientists conducted daily testing from 12 March to 10 August 2020 on healthcare workers at the Henry Ford Medical Centre in the US.