“These [items] are very good at destroying almost all viruses, which is why it is recommended so highly to regularly wash your hands,” said Dr Samuel Jones, group leader in the department of materials at the University of Manchester in the U.K. “The problem is that it is not easy to incorporate these into masks as they would be easily removed (leach out) and/or cause damage to the person wearing the mask,” he added.Both silver and copper would likely act as antivirals and there are previous examples of them being incorporated into textiles. They are trapped within the fibers matrix and so when wet/washed they leach out so they would only be effective for short periods. This is obviously not an issue if the mask is disposable or short term/one time use but would be for repeat usage,” said Jones.“One thing to try to understand would be how are they going to prove that the virus is destroyed and not just stuck to the mask. This is a subtle, but important difference. Viruses that are just trapped (intact) could potentially be released and go on to infect someone else. If the viruses is destroyed when it touches the mask then it cannot infect someone else but practically proving the difference in the lab is not trivial,” said Jones.