Cloth masks may reduce the risk of transmission of viruses, like the one causing Covid-19, only if washed every day at high temperatures, a new study from the University of New South Wales in Australia claims. The researchers stated that both cloth and surgical masks must be considered contaminated after use. For the study, published in the journal BMJ Open, data from a randomised controlled trial from 2015 was analysed. While they did not test for SARS-CoV-2, they included other respiratory pathogens like rhinoviruses, seasonal coronaviruses and influenza. The researchers did not advice handwashing the masks, instead the study backed WHO's recommendation of machine washing the masks in hot water at 60 degrees celsius.