Types of masks used against the spread of COVID-19
Advice on the use of masks has been changing constantly over the last few weeks based on emerging global evidence. There are several different types of masks that can be used depending on the need and setting.
Medical masks (also known as surgical masks):
These are made from a minimum of three layers of synthetic non-woven materials, configured to have filtration layers sandwiched in the middle. They are available in different thicknesses, and have various levels of fluid-resistance. They generally have a minimum of two levels of filtration and serve to reduce the transfer of saliva or respiratory droplets from the wearer to others/ the environment. They also decrease the likelihood of potentially infectious droplets from others reaching the mouth and nose of the mask wearer.
Respirators (also known as filtering facepiece respirators -FFR):
These are specifically designed for healthcare workers who provide care to COVID-19 patients in settings where special medical procedures are undertaken. They are available at different performance levels such as FFP2, FFP3, N95 and N99. Respirators are intended to protect the wearer when medical procedures aerosolize particles making them smaller than normal droplets in the air (within the healthcare environment). Healthcare workers using these types of masks should ensure that the respirator is sealed tightly on the face and is properly fitted.
Hand hygiene should be performed before putting on a clean mask and after removing it. The masks should be worn tightly around the chin and top of the nose. The wearer must be careful to avoid touching the mask while it is on the face and it should be immediately discarded if it becomes moist. Most importantly, wearing a mask must be combined with other preventive measures including performing frequent and appropriate hand hygiene and physical distancing of at least 1 metre (3 steps).
Non-medical masks are often made from of breathable fabrics in the home or commercially. These masks generally include multiple layers of fabric that cover the nose and mouth, are secured with ties or elastic loops and can generally be washed and re-used.
Cloth masks are currently being recommended in some countries as a means of source control in the general population. Although their protective effectiveness to the wearer is unknown, they may protect others if the wearer is a pre-symptomatic or an asymptomatic carrier (someone who has the infection but is showing no symptoms). In addition to the aforementioned factors, potential advantages of the use of masks by healthy people in the community setting include the reduction of potential exposure risk from an infected person during the ‘pre-symptomatic’ period or if an infected person is asymptomatic.
WHO is currently collaborating with research and development partners to better understand the effectiveness and efficiency of non-medical masks; and encouraging countries that issue recommendations for the use of masks in healthy people in the community to conduct research on this critical topic. Read here for more.