This guidance is based on evolving evidence, and provides updated advice on who should wear a mask, when it should be worn and what it should be made of.br br WHO has developed this guidance through a careful review of all available evidence, and extensive consultation with international experts and civil society groups.br br I wish to be very clear that the guidance we are publishing today is an update of what we have been saying for months: that masks should only ever be used as part of a comprehensive strategy in the fight against COVID.br br Masks on their own will not protect you from COVID-19.