Sun | Jan 17, 2021

COVID-19 killer? - Local doctors develop salt filters for masks to fight coronavirus

Published:Sunday | April 26, 2020 | 12:00 AMAnastasia Cunningham - Sunday Gleaner Editor
Dr Alfred Dawes, medical director, Windsor Wellness Centre & Carivia Medical Ltd, demonstrates how to make salt filters, using simple household items, to insert in face masks, which will effectively kill COVID-19.
The salt filters make any ordinary cloth mask a formidable weapon against the coronavirus
The best material is a regular coffee filter, but if this is not available then toilet paper squares, paper towels or napkins can be used.
The best material is a regular coffee filter, but if this is not available then toilet paper squares, paper towels or napkins can be used.
The filter is fully soaked in the salt solution, removed and left overnight to dry on a surface such as a countertop or glass bowl.

There’s still no known cure for the coronavirus disease 2019 (COVID-19), but one of Jamaica’s top medical practitioners, Dr Alfred Dawes, is today prescribing what he believes could be one of the most effective weapons in the global fight against the dreaded contagion.

And the best news of all about Dawes’ COVID-19 solution is that it is already present in virtually all domestic households.

Over the past few weeks, the respected surgeon, along with several medical colleagues, has been experimenting with table salt, based on its potent properties. They utilised several absorbent materials found around the home, such as coffee filters, toilet tissue and paper napkins, to develop a disposable filter which they say when soaked in a hot salt water solution and allowed to dry, could effectively kill, within 30 minutes, any virus that comes into contact with it.

“The process of making the filters is simple, cheap and the materials can be easily obtained,” Dawes revealed.

“The best material is a regular coffee filter, but if this is not available then toilet paper squares, paper towels or napkins can be used. They are soaked in a solution made by adding salt to hot water until no more added salt crystals can dissolve with stirring. The filter is fully soaked, removed and left overnight to dry on a surface such as a countertop or glass bowl.”

“How it works is that as the salt crystals reform during drying, the sharp edges basically cut through the covering of the virus, on contact, like small knives, killing them in about half an hour,” added the medical director of Windsor Wellness Centre and Carivia Medical Ltd.

If this “salt filter”, which is worn on the inside of cloth masks, proves to be as formidable a weapon as the medical practitioner believes, it could be a game changer in the fight against the highly contagious virus that has now infected close to three million persons globally and killed over 200,000. More than 800,000 persons have recovered worldwide, even as Jamaica now reports 305 confirmed COVID-19 cases and seven deaths, including a four-year-old who had a chronic co-morbid condition.


In an exclusive interview with The Sunday Gleaner, Dawes revealed that he got the idea of developing the “salt filter” from a conversation with a friend who was looking into the local manufacturing of masks. His research took him from the use of salt to preserve meat by killing the germs that caused spoilage, to showing that a special solution of salt used to treat surgical masks was effective in killing viruses that landed on them.

“I became more excited as I dug deeper and was convinced this would work when I told one of my mentors in surgery, Dr Loxely Munroe, from The Bahamas. He believed that the science behind it was sound and explained that when he was studying biochemistry in the United Kingdom, he used salt crystals to break up cells in order to extract the proteins inside. He was convinced it could work if I found the right filter on which to layer the salt,” said Dawes, who is a general and laparoscopic surgeon, a fellow of the American College of Surgeons, former senior medical officer of the Savanna-La-Mar Public General Hospital and former president of the Jamaica Medical Doctors’ Association.

Armed with the research, Dawes experimented with different materials and methods of treatment. It was at this point that he was assisted by Dr Rory Thompson, consultant pathologist and lecturer in the Faculty of Medical Sciences at the University of the West Indies.

The two set about examining the salt crystals under a microscope to determine which material and technique were better. Based on the experiments, a coffee filter proved to be the best of the low cost materials, with tissue paper in the form of napkins or toilet paper coming in second.

“I know the salt filters need to be evaluated as to how effective they are, but we do not have that capability in Jamaica. Neither do we have the time to wait. I hope someone with the resources will be able to take this idea and validate it in the field. But I strongly believe in the science behind it and I know it will cause zero harm to use the filters as long as we continue hygienic practices and social distancing,” he said.

“At worst, it will not offer one hundred per cent effectiveness but right now some improvement in the masks is better than using substandard cloth masks or reusing expensive masks and putting ourselves at greater risk.”

The doctor is therefore strongly recommending the use of the salt filter and hopes that it will help to decrease the spread of the deadly virus.

Dawes, a strong proponent of the view that “everybody should be wearing a mask whether or not they are showing symptoms of COVID-19”, further suggests that “social distancing, hand sanitising and the avoidance of face touching” are useful “to avoid getting droplets containing the coronavirus in your nose, eyes and mouth.

“We now know that the virus lives in extremely small droplets that are formed by even talking, and they hang around in the air for a long time, infecting persons and contaminating surfaces. So the root of the problem is droplet generation and this is where everybody wearing masks will significantly decrease the amount of droplets floating around with the virus, ultimately leading to less infections,” he said.


Last week, Dawes met with Minister of Health and Wellness Dr Christopher Tufton to discuss his findings.

“I saw Dr Dawes yesterday (Friday) and we spoke on it,” Tufton told The Sunday Gleaner yesterday.

“I appreciate the attempts by clinicians and others to assist and be involved in solutions to overcome the COVID-19 threat. This particular strain of the virus is new, so much is being done to develop new solutions to overcoming it. I would just want to be guided by clinical rules to finding solutions so as to give hope deservingly to citizens. I would, therefore, like to learn more about this particular solution,” the minister said.

Recent studies have confirmed that small droplets of mucous and saliva, microdroplets, are able to remain airborne for longer than initially suspected and may be a significant contributor to the spread of the new coronavirus. This emerging evidence has led to many health authorities, including the World Health Organization and Jamaica’s own ministry of health, changing their stance against asymptomatic persons wearing masks.

At his last COVID-19 press briefing, Prime Minister Andrew Holness announced that the wearing of masks in public was now mandatory.

With the global shortage of masks, and respirator type masks, such as the N95 and KN95, selling for as much as J$1,000 each, enterprising Jamaicans have created a cottage industry manufacturing cloth masks. However, health officials say these cloth masks are the least effective at protecting the wearer from viruses. This is the problem that the doctors hope to solve with their salt filters.



* Dissolve two tablespoons of table salt in quarter cup of hot water to soak 20 sheets of tissue/napkin or 25 coffee filters.

* Dip sheets/filters in solution until fully soaked.

* Let filter dry overnight on a smooth surface or countertop.

* Insert salt filter in pocket of cloth mask or wrap in handkerchief and properly cover nose and mouth.

* Coffee filters are best to use, followed by tissue paper (napkin or toilet paper). Both are inexpensive and easy to get.

* When the COVID-19 droplets hit the salt filter, it kills the virus within 30 minutes.

* Each salt filter is effective for up to 48 hours.