DISINFACTS | Issue 2/2020

INTERVIEW Class Max. total leakage (%) FFP 1 22 FFP 2 8 FFP 3 2 Which mask for which purpose? Personal protective equipment: Not all masks are equal: the molecular biologist Dr Marcus Reska from the German Advisory Centre for Hygiene (BZH GmbH) explains in which situations respirators should form part of personal protective equipment (PPE), which factors determine their leak tightness and what to pay attention to when putting on and removing masks. This interview reflects the German perspective of the topic. Dr Reska, masks are currently in great demand as protection against the novel coronavirus. When does the use of a respirator as part of the personal protective equipment make sense in the professional sector? In the hospital setting masks are differentiated into two types: firstly, there are multilayer face masks that cover the mouth and nose that are also referred to as surgical or medical face masks. Face masks are generally worn by patients to protect others, for example, against phlegm or larger droplets produced with a severe cough. Face masks are actually intended to be worn in the professional context of healthcare during operations by the surgical team to prevent contaminating the wound. Face masks are intended primarily to protect others against pathogens released from the wearer. In the hospital, this means that face masks are primarily for the protection of others! The situation is different for the second type of mask: the respirator. They form part of personal protective equipment and therefore, arguing by analogy, are used primarily for the protection of personnel. An FFP2 respirator is generally necessary for all aerosol-generating procedures. A respirator – protection class FFP2 or FFP3 – protects the wearer against microorganisms that are found in the smallest droplets, known as droplet nuclei, and prevents them reaching the airways. How well this is done depends for particle- filtering half-face masks or filtering face pieces (FFP) on the total number of leaks present, the total leakage. The total maximum leakage determines to which of the three protective classes used for filtering face pieces a mask is allocated. In which situations should masks form part of personal protective equipment? If a respirator is intended to effectively protect against airborne pathogens, such as open pulmonary tuberculosis, or aerosols, OHS guidelines advise wearing at least an FFP2 mask. For SARS-CoV-2, the Robert Koch Institute (RKI) currently recommends that FFP2 masks are preferentially worn if there are sufficient masks available and when directly treating patients with confirmed or likely COVID-19 (as at April 15 th 2020). In general, when choosing respirators for routine work, however, the risk of infection that is actually present, the practicability, the compliance of employees but above all the specific transmission route should also be taken into account. It is therefore useful if those responsible from the hygiene and occupational health and safety departments get together and agree which mask types are suitable for their setting. And then it is important to know how to actually use the relevant mask, right? What should I pay attention to? Firstly, fix the mask with the ties or the elastic strap in the middle of the back of the head and around the neck. Then compress the nose clip so that there are as few gaps as possible. Finally, position the mask comfortably on your face and below your chin. That’s it! ‘A respirator protects the wearer against pathogens in the air and prevents them reaching their airways.’ ‘Face masks are intended primarily to protect others against pathogens released from the wearer. In this hospital, this means that face masks are primarily for the protection of others!’ Dr Marcus Reska Respirators FFP (filtering face-piece) masks are divided into 3 classes. What is critical is the maximum total leakage. DISINFACTS 2/20 page 14