Non-medical masks may offer some protection against Covid-19, scientists say

With the rise of Covid-19 cases in Thailand, claims that non-medical masks are ineffective in preventing the spread of the disease are circulating online. This is misleading: scientists told AFP that these masks offer some form of protection. The US Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) recommend non-medical or tissue masks for the general public.

This complaint was posted here on Facebook on January 4, 2021.

“Non-medical mask = masks that are not designed for medical use = cannot be used for disease prevention,” says the Thai caption.

“Medical mask = hygienic masks that are for medical use = can be used for disease prevention, high performance.

“As for the Covid outbreak at the moment, if you keep your social distance, you can wear non-medical masks. But if you enter high-risk or crowded areas, you must wear medical masks ”.

The post contains two photos of a box of disposable masks with a red circle around the text “Non-Medical Mask”.

Thailand suffered a new wave of Covid-19 cases after an outbreak in a seafood market last month, with infections detected in 53 of the kingdom’s 77 provinces.

A similar statement circulated on Facebook here, here and here.

The claim, however, is misleading.

Mask types

The photo masks that circulate online are non-medical masks. These disposable disposable masks are recommended for use by the general public and are widely available in stores. These are not the same as surgical masks and N-95 respirators, which should be reserved for healthcare professionals, according to the Centers for Disease Control and Prevention (CDC).

Fabric Masks made of breathable material like cotton are also recommended for use by the general public. According to the CDC, “fabric masks not only effectively block most large drops (ie 20-30 microns and larger), but can also block the exhalation of droplets and fine particles (also often called aerosols) less than 10 microns. “

According to the World Health Organization (WHO), medical masks they are flat or pleated surgical or procedural masks; they are attached to the head with straps that go around the ears or the head or both. Medical masks are rectangular and comprise three or four layers. Each layer consists of fine to very fine fibers. These masks are tested for their ability to block droplets and particles.

On the contrary, non-medical masks or fabric masks they are made of a variety of fabrics and nonwovens, such as polypropylene. Non-medical masks can be made from different combinations of fabrics, layers sequences and available in different formats.

‘No guarantee’

Yong Poovorawan, a professor of pediatrics at Chulalongkorn University in Bangkok, told AFP that non-surgical masks “can be used to protect against viruses”, although “surgical masks perform better in protecting and preventing disease”.

“You can try to drip a drop of water [on a surgical mask] and you can see that nothing is leaking. However, there is no mask that guarantees 100% ”, he said in an interview granted on January 7, 2021.

“To the best [prevention] method is to wash your hands and maintain social distance. “

Theerawat Hemachuta, a professor at the Faculty of Medicine at the same university, said tissue masks offer some protection against coronavirus infection

“We must first understand that these viruses are usually transmitted through aerosol particles, such as when we talk or cough. These aerosol particles are large enough to stick to the fabric of the masks, ”he said in an interview on January 8, 2021.

“No mask can offer 100% protection, even surgical masks. But even non-medical masks offer some form of protection for the general public and should not be dismissed as ineffective. “

A report published in July by researchers at the University of Pennsylvania and the University of Cambridge said that “evidence remains that masks, including cloth masks, prevent the progressive transmission of infection.”

The CDC website has more guidance on the type of mask you should use.