The World Health Organization (WHO) published updated guidelines for the use of masks with regard to COVID-19, according to an announcement on Friday morning.
The new guidance is:
- In areas with widespread transmission, all healthcare workers should wear medical masks, not only workers dealing with COVID-19 patients.
- In areas with community transmission, people 60 years old or older or those with underlying conditions should wear a medical mask when physical distancing is not possible.
- Governments should encourage the general public to wear masks where widespread transmission and physical distancing are difficult, such as on public transport, in shops or other confined or crowded environments.
- Fabric masks should consist of at least three layers of different material.
According to the full report, an ideal fabric mask should consist of:
- An innermost layer of a hydrophilic material (e.g. cotton or cotton blends)
- An outermost layer made of hydrophobic material (e.g., polypropylene, polyester, or their blends) which may limit external contamination from penetration through to the wearer's nose and mouth
- A middle hydrophobic layer of synthetic non-woven material such as polyproplylene or a cotton layer which may enhance filtration or retain droplets.
The announcement, made by Dr. Tedros Adhanom Ghebreyesus, WHO Director-General, started by reaffirming previous guidance. "Masks should only ever be used as part of a comprehensive strategy in the fight against COVID," said Ghebreyesus. "[They] are not a replacement for physical distancing, hand hygiene and other public health measures."