Human-to-human transmission of SARS-CoV2 (that causes COVID19) is mainly through respiratory droplets that get generated when infected people cough, sneeze, or exhale. Therefore, in addition to following washing hands and avoiding touching the mouth, eyes and nose, it is necessary to wear masks under some circumstances to prevent human to human transmission of infective droplets.
There are two types of masks which are recommended for COVID19 patients and their contacts, caregivers and healthcare workers interacting with them and also people with symptoms (fever, cough, breathlessness). Learn more about official guidelines on the use of masks by public here (https://www.mohfw.gov.in/pdf/Useofmaskbypublic.pdf)
Triple layer surgical masks are disposable, fluid-resistant masks, made of non-woven fabric. They are designed to act as a barrier for large droplets emitted during coughing/sneezing/talking by the wearer to avoid spreading the infection. They provide substantial protection only up to 0.5 micron. Most surgical masks are NOT designed to seal tightly to the face and should not be relied upon to help reduce exposure to inhalable airborne particles. Make sure that you learn the right technique to wear and dispose the mask.
Respirator maks with high filtration efficiency (N95/FFP2 or better) can filter particles down to the size of the coronavirus (which is around 0.1 microns). However, N95 respirators aren’t one-size-fits-all. They actually must be fit-tested before use in order to make sure that a proper seal is formed. If the mask doesn’t seal effectively to your face, you won’t receive the appropriate protection. It’s also important to note that a tight seal can’t be achieved in some groups. These include children and people with facial hair.
Homemade masks made out of cotton fabric, scarfs and antimicrobial pillowcases should be treated as last resort option. They should preferably be used in combination with a face shield. While homemade masks may offer some degree of protection, they offer less than 50% protection than surgical masks or up to 50 times less protection than N 95 respirators.
Valved respirators make it quicker and easier to exhale air than their non-valved counterparts. This makes them more comfortable to wear over a long time and leads to less moisture build-up inside the respirator. This is particularly useful with the higher rated filters (N100/FFP3), which require more force to exhale through. However, valved respirators may not be optimal in settings where you want to stop the wearer from spreading the infection. If the wearer is ill, their out breath / coughs / sneezes will make their way through the mask valve, and into the air, without filtering. This is due to the valve opening when exhaling. Please consult your doctor to get a proper recommendation on which mask is good for you.
Due to high demand, health workers and hospitals alike are looking into reusing N95 masks. We do not yet have a reliable data on whether reused masks increase cross contamination risks for COVID19 patients. Available data suggests that heating the mask with hot air in oven at 70 deg C for 30 min or treating them with high energy UV rays for 30 min or hot water vapor from boiling water for 10 min or treating them with hydrogen peroxide vapors will affect their filtration efficiency only marginally, thus allowing for reuse. Please consult with your doctor before reusing your N95 masks.
