Rain could limit the effectiveness of face masks in preventing the spread of COVID-19, the World Health Organization (WHO) and Public Health England have warned.
They said all face masks that get wet or damp need to be replaced immediately in order to maintain their effectiveness.
Prof. Karol Sikora, a former WHO cancer program chief, told The Times: “Moisture makes masks porous, and because of this all types of mask are essentially vulnerable in damp weather.”
Tim Spector, professor of genetic epidemiology at King’s College London, told the newspaper: “It would now be useful if clear advice were issued to the public. Masks need to be changed regularly and this is particularly important to understand in damp and wet weather.”
Dr. Aseem Malhotra, a consultant cardiologist in the UK, said this possible failing in standard protective masks should have been made obvious to people early on, and should be of particular importance with Western nations entering the wetter winter months.
“It is obvious that masks will get damp as people shop and travel in bad weather,” he told The Times. “There has been no public campaign to make people aware that this can make their masks ineffective.”