How To Decontaminate Facemask For Reuse During Covid-19

Facemask decontamination

COVID-19 pandemic brought about so many problems. With limited availability of personal protective equipment (PPE) for health care workers, there is a major shift for alternatives. One area many people are looking at is how long can this equipment be used and if possible reuse. This is because the manufacturer recommendation for most of these equipment are usually one for a patient after which they are properly disposed of.

But that cannot be possible in a pandemic. When a medical doctor is required to see up to 100 COVID-19 patients in a hospital, changing PPE for each patient will cost the country a huge amount of money. The current recommendation now is to use one for all the patients and dispose of them properly. Presently, the health care system of most countries have been overstretched and that is not even feasible right now.
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The last alternative is to decontaminate. There is no approved decontamination method. Any method here or in other sources only tries to gather information from many personal or groups of personal research into the subject matter. In most cases, they do not meet international standards for research because they did not answer some basic questions. For example, one researcher did find out that the virus does not remain in a decontaminated mask after using a particular method but failed to give a report on the efficiency of the mask after the experiment. This is because, in most times, the method may work but can destroy the mask.

A good decontamination method must meet some requirements. Unfortunately, most of the present research failed to meet all. Here, it is recommended that a decontamination method should;

1. Kill all living pathogens

2. Retain its ability to filter

3. Leave no chemical hazard

4. Does not destroy the material

For decontamination to be carried out successfully, it is good to prevent contaminating the PPE during the process. Use hand gloves, eyeglasses and liquid-resistant gown to protect yourself and the decontaminate PPE.

There are so many types of PPE out there that require decontamination. However, let us focus on facemask. The type of facemask will determine the best sterilization method.

Surgical Facemask

This is the most common facemask around. It is disposable. It is recommended that it should not be used for more than a patient or four hours. It should also be changed when it becomes soiled or damp. With the pandemic holding the world to a ransom, some authorities are lowering their stand on the matter. Some are saying it can go for 12 hours. There is no approved method or even research on how it can be decontaminated and reused. What many people do is to use heat over a gas cooker or put it in hot water. There is no evidence if this works.

Home-made Face Mask

This is a mask sewn at home using clothes in the house. It offers some degree of protection. It protects the wearer to some extent and most importantly prevents the spread of COVID-19. A little evidence from countries using it has shown that they have been able to flatten the curve.

Since it is sewn from home materials that can be washed, detergent and water is enough to disinfect it. Warm water is preferred. After washing, dry.

Elastomeric Facemask

This is the only facemask that is approved for decontamination. But it is very expensive. Another disadvantage is that it makes vision and audio difficult for the wearer. The different parts can be decontaminated using different methods. Cartridges can be wiped with alcohol quaternary microbial cloth. Some parts can be sterilised in an autoclave. Cleaning is done by washing in a mild detergent at 110° F after which it is rinsed with cold water and drains. Disinfection, on the other hand, is done by immersing the parts in a solution of water and 0.1 % household bleach for 2 minutes. Rinsing and drying follow.

Heavy Duty Respirator

This includes N, P and R series of facemasks. They filter air between 95 to 100 percent. They are not to be used for a long time and are not reusable. However, with the current situation of things, much research has been done and more ongoing on how to effectively decontaminate it without losing its filtration ability. Early results have been modified with more results showing otherwise. And it is obvious that many more adjustments will be made in existing suggestions as more research shed more light on it.

Presently, there are so many methods that are out there to decontaminate heavy-duty respirator. The truth is that none have met the gold standard of achieving >6 log reduction of the viable virus without destroying the mask.

However, of all the methods some have shown some positive results. A good example is steam.

Steam

Steaming for 10 minutes at a high degree can kill the virus without destroying the mask. Some recommend 170° F for 30 minutes.

Another method that looks like steaming is placing the mask on top of a container for some minutes that contains boiling water. The water is best boiled with an oven. Both parts of the mask can be decontaminated by turning it after a while. There is little damage done to the mask. But mask with paper should be avoided in this method.

Oven

If you must use an oven, consider the health implications. It is better to use a dedicated oven for this. Best to get a new oven for your food while the old one is used for decontaminating used masks. Heating the facemask for some minutes can kill all the virus without destroying the mask.

Hydrogen Peroxide Vapour

From the little I was able to gather, this is by far the best of all the methods. But it will be difficult at home except in the hospital. I will dig a little deeper. Hydrogen peroxide is known to deactivate bacterias. The vapour is no exception. At the right concentration, the vapour kills bacterias exposed to it. No research yet on its ability to kill COVID-19 virus. However, because viruses are weaker than bacteria, it is expected to be a perfect killer of the virus. And since masks need to be decontaminated not just from COVID-19 virus alone but from other microorganisms, it makes for best use. Besides, there was no significant reduction in the efficiency of the mask using this method. And it can be used up to 50 rounds without any significant reduction in efficiency.

Ultraviolet (UV) Germicidal Irradiation

This method is good but not foolproof. It requires careful screening during the process. It works with line of sight. The mask must be placed in the line of the UV-C lamps. To decontaminate the reverse side, the mask is flipped over.
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According to an experiment, a dose of 1Joule/square centimetres with a short wavelength of 254nm was able to inhibit severe acute respiratory syndrome (SARS) and middle-east respiratory syndrome (MERS) virus was inhibited. It retains its efficiency with this. Even exposure to higher doses did not show significant damage. At a very high dose, the material was a little bit damaged after like 20 times. They end up recommending that this method can be used for a heavy-duty mask up to 20 times using the standard 1j/SCM.

How Many Time

All the decontamination methods here are good. But frequent and regular decontamination can finally damage the mask. Since research is still ongoing, some if these answers will be made available maybe soon.

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