Covid-19 – new Coronavirus prevention measures

Update 2020.10.23 – Today one new study (from 25’th of May 2020) has come to my attention ( ) that once again confirms the effectiveness of using NaCl (table salt) to create a virus-fighting layer on your existing face mask. 

As such I do now recommend once more the procedure for transforming your DYI and other masks into veritable virus-killers. In the study, they recommend using an extra layer on top of the normal N95 mask or using inner layers where possible (DYI masks). I also think is better this way as this layer can and should be replaced regularly once it becomes wet (possibly a few hours use only).

Update 2020.03.20 – I have updated the post to reflect the answer from the team that published the research in Nature magazine. They DO NOT  RECCOMEND using this DYI process as the effectiveness and benefits of such a modification can’t be properly quantified. 

During the last month, I have been actively studying the new coronavirus outbreak, its dangers, and the prevention solution available.
The point of prevention solutions has been somewhat eclipsed by the other types of news available like the current status of the outbreak, the quarantine measures taken by some states, the research on mortality, conspiracy theories, and so on.
The talk as been much less than needed on active prevention measures with contradictory information available on the use of respiratory masks, medicines and other prevention tools.
I think there are some things that we should agree on before continuing:

  • the outbreak poses a great danger to us (with 2.6% mortality and a higher contagion rate than already contagious influenza viruses and not least the lack of antibodies to prevent for subsequent illnesses);
  • the incubation stage is by far longer than previously observed (from 2-3, 14 to up to 28 days) in other viruses and the fact that many of the cases can be mild poses an even greater danger of entering an endemic stage in the human population;
  • even with the draconic measures that the Chinese government took the spread of the virus couldn’t be contained to the Hubei region and has now reached a growing number of countries;

Taking this into consideration the only means to counteract the spread of the new virus is to implement measures much earlier than the time when the virus is already present in the community.

Basic measures are: 

  • frequent handwash;
  • self-quarantine in case of symptoms or even in case of travel to regions in which the virus has been already confirmed;
  • healthy lifestyle;

But these measures are not enough. There is a need for community-centered measures like:

  • cancelation of public assemblies (concerts, meetings, worshiping in curches)
  • frequent disinfection of public transport, public community centers (city halls, shopping malls)
  • even the hourly disinfection of shopping charts in local supermarkets could be a great tool for prevention, not to mention the pharmacies where people with flu-like symptoms will likely go in search of medicines

Even these measures that are already in place in some areas are not failproof. We would need a vaccine to fight this coronavirus but news about the lack of antibodies in blood plasma of recently discharged patients is not good news when we think of the effectivity of a said vaccine.

It is already understood that if we can protect our airwaves and mouth good enough we might not catch the virus. Most of the measures of hand disinfection are because usually, we use hands to clean our nose and mouth and eyes regularly.

The masks we use now have a limited effect on stopping the virus spread because:

  • low availability of the masks and high prices for good masks;
  • we are not trained to correctly use and dispose of the masks (all respiratory masks are single-use);
  • it is technically impossible to have enough masks for everybody, as would be required to use 2-3 masks per day per person;

This study explains the Effects of Air Temperature and Relative Humidity on Coronavirus Survival on Surfaces   From this study, we can conclude that there is a high probability that also the new coronavirus can survive on surfaces for many days and this adds to the effectiveness of respiratory masks.

During my research on this subjects, I have found this scientific paper Universal and reusable virus deactivation system for respiratory protection. It presents a way to use NaCl (table salt) to create an antibacterial and antiviral layer deposit on the normal respiratory masks. There are numerous articles that present this study like for example this from American Council on Science and Health 

The conclusion is simple. We have all the tools we need to create an effective prevention method. Sadly this information has not yet reached the institutions that ought to protect us, governments, health providers, respiratory masks manufacturers. For example WHO has not responded for example to any of my emails regarding this study nor its director. This is one of the reasons I choose to present this here. I will try to explain in the next few paragraphs how to make your own respiratory mask with antiviral and antibacterial properties. This is how i did my own masks and does not represents an professional advice whatsoever.

Update 2020.03.20. Moreover i have contacted the teams that published the study and they replied to me as follows. They have warranted concerns on coating existing masks as it’s impossible to controll and check the efficienty of such coating on the different materials used in each existing mask type.

“Regarding the mask, the final product is not ready yet. We have demonstrated a concept using a single layer filter, but to make a final product we have to do scale-up research. Single layer and three layers are quite different, and there are many critical factors that we need to consider. If not properly designed or prepared, filter fibers will be damaged and it cannot provide protection against respiratory disease. Actually, it will accelerate the biological contamination. So, I really do not recommend trying to modify current mask. It cannot be made by DIY process.”


  • Table salt in abundance (i have used very fine granularity – recrystallized salt)
    • it is hard to find pure salt but during my tests, I have not seen a morphological difference (quality of salt layer) compared to table salt that contains iodine. As iodine is also an antibacterial agent it should do no harm in the quantities presented in normal table salt.
  • Water
    • again one can use distilled water but we can also find some clean water (not exactly tap water) that we can out of an abundance of caution boil before use;
  • Tween 20 – also known as Polysorbate 20
    • this is readily available from many sources as it is used as an additive in many industries including the food industry and cosmetics industry;
    • according to the latest study, I’ve mentioned at the beginning of my post even without using Tween 20 the method dramatically increases filtration efficiency;

The process:

  1. Saturate the water with salt, to do this mix continuously water and salt until you can see the salt added will not dissolve anymore; To be technically correct you should bring the water to a temperature of 90 degrees celsius as this is the temperature required for the water to dissolve the maximum amount of salt possible;
  2. Add 1% Polysorbate 20 (10 ml for 1 liter of salt-saturated water) and mix; Why Polysorbate is required? Let me explain. Normal masks are hydrophobic (will not readily absorb water). We need to get the salt water to penetrate the masks fibers as much as possible. So we use Polysorbate 20 witch is a wetting agent (helps water enter the fibers of the mask). Also, polysorbate 20 is also good to stabilize the salty mixture we just made so it can be kept for later use.
  3. Apply generously over the layer that you intend to prepare as described in the latest available study. I initially recommended applying it over the entire mask surface (the outside of the mask). “You can also dip the mask in this mixture but that would mean that the mask will be completely coated and then when you will use the mask salt will be in direct contact with your skin. By the way, this is not necessarily a bad thing because there are many that recommend salt skin treatments for skin problems.”
  4. Dry the layer/mask. I have not seen big differences during a faster or slower drying process as the mask fibers will help in the recrystallization layout of salt but on flat surfaces faster drying leads to the formation of bigger salt crystals so I do recommend a slow drying method. In the study, they talk about 37 degrees “dried in an oven (Isotemp Incubator, Fisher Scientific) at 37 °C for 1 day” cited from the scientific article mentioned earlier.

This a microscope picture of a normal mask without the salt layer:

This is a picture with the salt layer added:

The mask or the extra layer can be ready to use. The mask/layer is not hydrophobic anymore. It will readily absorb water and, in the same manner, it will absorb virus aerosols exposing the virus to a high salt concentration and rendering it inactive after 5-6 minutes from contact. The effectiveness of this process is tested at normal room temperatures and humidities keep this in mind when using the mask outside in very low temperatures for example. You should take the mask off after 10 minutes on entering a 25 decrees celsius environment.

The mask created using this process I think it should be effective and safe to be used multiple times. I expect about 5-10 times until the salt layer loses its continuity so also keep this in mind and make sure the salt is still there. Don’t use it in a very humid environment that can deplete the salt layer, don’t use it in the direct rain, etc.

If using a paper towel as an extra layer for an existing mask, as described in the latest study, they recommend changing it every 2 hours.


  • What types of masks/layers can be used?
    • You can use any available mask type. Of course, preferably masks rated FFP3 or N99 but this process will work on any mask type out there.  Update 2020.03.20 – due tot the very different materials used in the mask making process the efffectivness of coating different masks can’t be propperly known or estimated.
    • as it is stated in the latest study you can even use a paper towel as an extra layer for your DYI mask or any other type of material like polypropylene-based materials. It can be inserted as a middle layer of DYI masks or as a cover layer of other types of existing masks.
  • Why don’t manufacturers implement this in masks production?
    • I can only think there are two possible reasons:
      • they don’t know yet as the research on this is from 2017
      • manufacturers will not profit from having such a simple procedure extend the life of a respiratory mask; they prefer to sell single-use masks in big quantities;

The opinions presented in this article are not medical advice whatsoever. Are my own personal opinions. You can always seek professional advice if you wish to use any of the information presented here by me and you should also check with your doctor if you have allergies to salt and any other compounds used here like polysorbate 20.

Update 2020.03.20 – i do not reccomend making such DYI masks. I hope that the oringial study team can contiunue the research and include the coating of existing masks in it.

I welcome any feedback on the informations presented here so don’t be shy to comment.


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