Do not wear a mask if you are well read a warning plastered across the front of Singapore main newspaper on Friday, as authorities around the world sought to calm panic buying of masks seen as a guard against the fast-spreading corona virus. In neighboring Malaysia, the government urged people to always have masks and hand sanitizers ready, similar to advice by authorities in Thailand and Vietnam. Conflicting messages have sowed confusion over how to protect against an epidemic that has claimed over 200 lives in China and spread to over 20 countries, with some experts saying wrong handling of masks could even increase infection risk.

Official guidance from the World Health Organisation and the Centre for Disease Control and Prevention makes no mention of wearing a face mask as a preventative measure against the virus – but their websites do not specifically advise against them. Australia and Taiwan have …