With Omicron, Experts Warn Against Cloth Masks

Omicron is once again making people think twice before reaching out for their colorful, reusable cloth face masks.

"They can be really good or really terrible," depending on what fabric is used, said Trish Greenhalgh, professor of primary health care services at the University of Oxford.

Double or triple-layer masks made of a mix of materials can be more effective, but most cloth coverings are just "fashion accessories," according to Greenhalgh.

As the highly infectious omicron causes Covid infections to surge worldwide, governments around the world are tightening restrictions to try and stop its spread. Earlier this month Britain reintroduced compulsory mask wearing on public transport, shops and in some indoor venues, having previously relaxed the rules in the summer. Throughout the pandemic, authorities in different places have said different things about when and where healthy people should wear face masks and what type of coverings they should choose.

The main issue with a cloth covering is they don't have to meet any kind of health standard, says Greenhalgh. In contrast, those manufacturing N95 respirator masks, for example, have to make sure they filter out 95% of particles.

Still, good filtration is useless if the mask doesn't cover your nose and mouth properly. You also need to be able to breathe easily through the mask, Greenhalgh said. Environmentally or money-worried consumers used to reach out for cloth masks because they could be washed but there are reusable coverings that meet filtration standards available now.

Canadians are already being advised to ditch single-layercloths masks in favor of tighter fitted ones.

"The issue here is if you have a single-layer, the ability to filtrate is absolutely minimal and doesn't make a difference whatsoever," said Peter Juni, head of Ontario's Science Advisory Table in an interview with CTV news last week.