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

As Covid-19 cases increase in Thailand, it is claimed that non-medical masks are ineffective in preventing the spread of the disease, being distributed online. This is misleading: scientists told AFP that these masks provide some form of protection. The US Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) recommend non-medical or dust masks to the general public.

This claim was posted on Facebook on January 4, 2021.

“Non-medical mask = masks not used for medical purposes = can not be used for the prevention of diseases,” reads the headline of the Thai.

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

As for the current Covid outbreak, if you keep social distance, you can use non-medical masks. But if you enter high-risk areas or overcrowded areas, you must use 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 following an outbreak in a seafood market last month, with infections detected in 53 of the kingdom’s 77 provinces.

A similar claim has been circulating here, here and here on Facebook.

However, the claim is misleading.

Mask types

The masks in the photo distributed online non-medical masks. These disposable disposable masks are recommended for use by the general public and are widely available in stores. It is not the same as surgical masks and N-95 respirators, which must be reserved for health workers according to the Centers for Disease Control & Prevention (CDC).

Dust masks made of breathable material such as cotton is also recommended for use by the general public. According to the CDC, “cloth masks not only effectively block most large droplets (ie 20-30 microns and larger), but can also block the exhalation of fine droplets and particles (also often called aerosols) smaller than 10 microns. ”

According to the World Health Organization (WHO), medical masks are surgical or procedures that are flat or wrinkled; they are attached to the head with straps that go around the ears or head or both. Medical masks are rectangular and consist of 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 material masks is made from a variety of woven and non-woven materials, such as polypropylene. Non-medical masks can be made from different combinations of tissues, layer layers and are available in different shapes.

“No guarantee”

Yong Poovorawan, a professor of pediatrics at Chulalongkorn University in Bangkok, told AFP that non-surgical masks “can be used to protect 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 seeping through. However, there is no mask that can guarantee 100%, ”he said in an interview on January 7, 2021.

‘The best [prevention] method is to wash your hands and keep social distance. ”

Theerawat Hemachuta, professor of the Faculty of Medicine at the same university, says dust masks provide some protection against coronavirus infection

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

No mask can provide 100% protection, not even surgical masks. But even non-medical masks do provide some form of protection to 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 states that there is still evidence that masks, including cloth masks, prevent the transmission of infection.

The CDC’s website contains more guidelines on what type of masks to wear.