A specialist in respiratory medicine, David Hui, on Thursday said people who are at a greater risk of catching Covid-19 should consider wearing a cloth mask on top of a surgical mask, to increase protection against the highly transmissible Omicron variant.
The expert was echoing advice from microbiologist Yuen Kwok-yung.
Speaking on a radio programme, Hui said a cloth mask can push the edges of a surgical mask closer to the face and ensure a tight and snug fit.
"Surgical masks are generally quite loose. Wearing a cloth mask on top of them can close the gaps and reduce potential exposure to respiratory droplets," he said.
Hui said residents of Tuen Mun, where multiple Covid infections have recently been discovered, and people who use public transport could also think about wearing two masks at the same time.
Speaking on the same programme, Yuen said people with chronic diseases or who can't receive a Covid jab, as well as workers doing high-risk jobs such as those at the airport, could also consider wearing double masks.