Are double masks needed to combat coronavirus variants?

With the emergence of highly infectious coronavirus variants, along with a rise in the number of COVID-19 cases in Singapore, having good protection against possible infection is an area of concern to many. NUS experts Professor Teo Yik Ying and Associate Professor Hsu Li Yang from the NUS Saw Swee Hock School of Public Health (SSHSPH), give their opinion on whether the current safety measures are sufficient, or if there is a need to increase them.

“Presently, the understanding on the characteristics of the new variants is that they are transmitted in the same manner. People infected with some of these new variants have been associated with having a higher viral load,” said Prof Teo, Dean of the SSHSPH.

Assoc Prof Hsu, Vice-Dean (Global Health) and Programme Leader of Infectious Diseases at SSHSPH, remarked that the UK and South Africa variants of the virus appear to be more efficient at attaching to and invading human cells. However, he noted that the World Health Organisation has not changed its stance to recommend triple-layered masks in the community as yet.

While the public may be feeling worried about increased safety measures, Prof Teo shared, “The issue actually is about people following the current measures properly, including the proper wearing of masks, rather than to add on additional or stricter measures.”

Although some experts in the United States have advocated the use of double face masks as added protection from the new variants, the mass-produced high-quality masks in Singapore should be effective if used correctly.

“Masks on their own do not offer total protection against infection, but wearing one works in tandem with preventative measures such as physical distancing and hand washing,” explained Assoc Prof Hsu.

“In terms of face masks, there has always been a recommendation on three-ply masks, and even the masks distributed by the Singapore government come with specific instructions on allowing additional middle layer filters to be inserted,” Prof Teo explained.

Properly constructed 3-ply surgical masks have been shown in research settings to provide amongst the best performance in terms of serving as a barrier against droplet projections. However, properly constructed reusable 3-ply cotton masks already are sufficiently efficient at minimising droplet projections.

So, what type of face mask should we be wearing? “By all means, use a surgical mask if there is a stable supply that does not compromise on access by healthcare workers and key frontline staff. But there is presently no evidence to suggest that there is a need to switch to higher-quality masks when one is moving about in public spaces. What is more important, is to wear the mask properly,” Prof Teo said.