LONDON: Many people across Asia wear face masks to try and protect themselves against Covid-19, the disease caused by the new coronavirus. In Europe and the United States, masks are less commonly worn, but many people are asking: Should they wear them during the pandemic?

The World Health Organisation’s advice is that if you are healthy, you only need to wear a mask if:

• You are caring for someone with suspected or confirmed Covid-19 infection.

• You are coughing or sneezing yourself, or suspect you might have Covid-19.

Masks work by capturing droplets that are dispersed in coughs, sneezes and breath — these are the main transmission route of the new coronavirus.

There are two main types of mask: surgical masks, which are strips of fabric worn across the nose and mouth and closer-fitting ones sometimes called respirators.

• Close-fitting masks — such as N95 ones — can offer good, but not total protection against infectious droplets, while the next rank up — the N99-rated masks — can give better protection, but some find them difficult to breathe through.

• The “N” rating relates to the percentage of particles of at least 0.3 microns in diametre that the mask is designed to block: N95 masks stop 95pc and N99 masks stop 99pc.

• Some masks have a valve in the front to help prevent moisture in exhaled breath condensing on the inside, making the mask wet and more liable to virus penetration.

• Masks are only effective if you combine wearing them with frequent handwashing and ensure you don’t touch your face.

• Anyone using a mask should make sure their hands are thoroughly cleaned with soap and water or an alcohol-based hand sanitiser before putting it on.

• The mask should cover your mouth and nose, and there should be no gaps between your face and the mask.

• As much as possible, avoid touching the mask.

• When the mask becomes damp, replace it with a new one. Do not re-use single-use masks.

“Wearing a mask can also reduce the propensity for people to touch their faces, which happens many more times a day than we all realise and is a major source of infection without proper hand hygiene,” said Stephen Griffin, an associate professor at Leeds University’s Institute of Medical Research.

Published in Dawn, March 26th, 2020