We need to be able to disinfect our homes safely during a viral outbreak.
Those people who are “essential” and can’t completely shelter at home, have even more need to be able to keep their work and home environments clean.
Since, as a pharmacist, I am not able to completely stay at home, this topic has been at the forefront of my mind lately.
I worry about being in an environment where I might be exposed to a potentially deadly virus and then, bringing it home to my family.
So, I want to do what I can to decrease my exposure to the coronavirus. Part of my strategy for doing that is to keep things clean—first at work, and then at home.
When I’m obsessing over something, I need to just completely delve into the topic. I don’t want to be obsessive or controlling of things I have no control over but, on the other hand, I need to know what it is I can or cannot control.
That’s just how I deal with uncertainties.
Here’s what I’ve learned from my research of what the medical literature and scientific evidence shows us about common household cleaning chemicals and their effectiveness at fighting viral or bacterial infections.
It has reinforced much of what I knew, but has also taught me some new things.
I hope it will be helpful to you, as well.
Not all viruses (and bacteria) are susceptible to the same chemicals. Choosing surface disinfectants can be tricky if you don’t choose the correct one, and mixing cleaning chemicals can cause chemical reactions that are dangerous and potentially deadly.
So, let’s touch on some of the more common viruses and how we can safely and effectively clean the hard surfaces of our homes.
(As a side note: killing bacteria is generally easier than killing viruses. So, we’ll focus on decreasing viral contamination, and we can assume that that will also take care of bacteria.)
Where Viruses Live
Whether or not a virus is really “alive” is an old debate, since viruses don’t have their own metabolic function.
Let’s leave that debate to others because right now, it is a completely academic debate and, more importantly for this discussion, it doesn’t matter.
Viruses, like parasites, need a host to multiply and continue to spread. Then they are “shed” off of the host from various areas of the host’s body. Generally, those areas are areas where body fluids come from: mucus from nasal passages or lungs (sneezing, coughing, breathing), vomitous, urine, feces, and (potentially) sweating.
So, viruses will be found on the hard or soft surfaces of our environment wherever people touch, cough, sneeze, or use the bathroom.
Noroviruses, which cause what we commonly think of as stomach-flu (which isn’t actually a flu virus), has been shown to be able live on a dry surface for up to several weeks. Noroviruses are found on floors, tables, chairs, handles, doorknobs—anywhere that hands touch or vomitous and feces splash. I know. Ew.
Influenza viruses, both A and B strains, have been shown to live on a hard surface like stainless steel or plastic for up to 48 hours. On soft surfaces, like paper or tissue, they live for 8 to 12 hours.
The most common places for Influenza virus to show up are the areas where our hands touch—remote controls, computer keyboards, countertops, handles and knobs, phones, toys.
So, although respiratory viruses have been identified in feces, they are more concentrated on body parts that touch mucus or sputum from coughing and sneezing.
That means they are more likely to be on the toilet handle then on the toilet seat.
Don’t forget the soft surfaces—dish rags and sponges, hand towels, cleaning cloths. These need to be washed or replaced regularly. When there is an active infection in your home, or if you know there has been exposure, but no one is symptomatic, it’s a good idea to use disposable paper towels to dry hands.
There will be some virus on floors and carpets but not in the same concentrations as areas where our hands touch.
A recent study published in NEJM found that SARS (Severe Acute Respiratory Syndrome), a type of coronavirus similar to CoVID-19, lived on a softer surface (cardboard) for up to 24 hours and on stainless steel and plastic for up to 3 days.
There are no recent studies of this type specifically about the current coronavirus (CoVID-19), but the SARS viral study will give us an indication of what is probable for CoVID-19.
So, assume that CoVID-19 will live on a hard surface for 3 days and found in the same places as influenza since it is also a respiratory virus that is spread in the same way.
Effective Cleaning and Disinfecting Solutions
The effectiveness of the cleaning solution is largely dependent on the structure of the virus—enveloped on non-enveloped (naked).
Enveloped viruses have a phospholipid bi-layer surrounding them that the virus takes from the host (mammalian) cell. It may give them an extra layer of protection while on a dry surface but makes them more susceptible to some of the most simple cleaning solutions like soap and rubbing alcohol.
Both Influenza and corona viruses are enveloped, while norovirus is non-enveloped.
Soap and Water for Hand Washing Effective for Viruses
Soap is particularly effective against enveloped viruses as the soap will cause the lipid part of the envelope to break down.
Hand washing with plain soap and water has been shown to be more effective than using rubbing alcohol-based hand sanitizers.
When hand washing, the shearing action will also rid the skin of virus or bacteria. Washing hands for 20 seconds has become the standard, making sure to get in between fingers and the back of the hands. None of this lazy, 5 second, palms only stuff.
A note about long fingernails: they’re gross. Also, they hide bacteria and viruses so, keep them short.
Rubbing alcohol is commonly available in two different forms: ethyl alcohol and isopropyl alcohol. Isopropyl alcohol is most commonly found at your drug or grocery store and usually in a 70% concentration.
Concentrations of 90-99% can be specially ordered by your pharmacist, but the World Health Organization (WHO) has shown that these concentrations are not be as effective as concentrations between 60 and 80%.
It seems that some water needs to be present for the alcohol to be most effective.
At 60% to 80% concentration ethyl alcohol is effective against both enveloped (influenza and corona) and non-enveloped viruses (norovirus).
Isopropyl alcohol is only effective against enveloped (influenza and corona). Another reason why hand sanitizer is not as effective as hand washing.
Hydrogen peroxide 3% is effective on surfaces or skin as a disinfectant against all viruses (enveloped and non-enveloped).
It has a wide kill spectrum and works quickly. It is also very safe and non-toxic. Hydrogen peroxide creates water and oxygen as it reacts so causes almost no irritation to skin, eyes, and lungs and also is friendly to the environment.
Higher concentrations of 6 to 7% can be irritating to tissues but is generally only used as a sterilizer for medical instruments.
Distilled White Vinegar
Vinegar is an organic acid whose active ingredient is acetic acid. The typical concentration of acetic acid in store-bought vinegar is 5%.
Small studies have shown that different concentrations of vinegar have differing effectiveness on bacterial and viral load, as expected.
After a contact time of 30 minutes, one study showed 6% vinegar killed M. Tuberculosis.
A 10% malt vinegar was shown to be effective against influenza in this study: (https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0008987).
Researchers in this article stated,
“However, the addition of any of 1% bleach, 50% and 10% malt vinegar and 1%, 0.1% and 0.01% washing up liquid were all effective at rapidly reducing viable virus below the limit of detection, while a low concentration of vinegar (1%) was no more effective than hot water alone.”
Concentrations of acetic acid as high as 30% (sometimes called cleaning vinegar) can be bought at Home Depot.
Also, contact time, depending on concentration, can be anywhere from 10 minutes to hours.
So, use vinegar if that’s all you have, but it isn’t as effective as the others we talk about in this post.
Chlorine bleach is one of the most effective antimicrobials around.
Most household bleach is a 5% concentrated solution.
The following study recommends a 0.05% diluted solution for disinfection: https://www.ncbi.nlm.nih.gov/books/NBK214356/
To make a 0.05% diluted solution, use 1 part bleach to 99 parts water.
When measuring out “parts”, the unit of measure can be anything you would like. An appropriate unit of measure for a large spray bottle would be ounces or tablespoons, for example.
So, you would measure 1 ounce of bleach for every 99 ounces of water. If you have a small spray bottle you can use tablespoons or teaspoons as your unit of measure: 1 tablespoonful bleach to 99 tablespoonfuls of water. Adjust the quantities to allow for the amount you need.
The Danger of Mixing Cleaning Chemicals
Since no one cleaning chemical kills all things, you may be tempted to mix cleaning solutions.
DON’T DO IT!
Mixing cleaning chemicals generally results in poisonous gases that are dangerous and potentially deadly.
Bleach + ammonia = chloramine gas
Bleach + vinegar (or any acid) = chlorine gas
Bleach + rubbing alcohol = chloroform
Hydrogen peroxide + vinegar = paracetic acid (corrosive and irritating to lung and other tissues)
Rules of Engagement for Killing and Disinfecting Viruses
Before using any of the above solutions, it is recommended that any loose dirt, food, or other material is cleaned away with soap and water before spraying the hard surface.
Contact Time Matters
Enough contact time with the virus needs to be allowed to render the virus ineffective.
The amount of time depends on the product and how effective it is. Always spot-test a surface using a new cleaner as they can be damaging or corrosive.
A 0.05% bleach solution disinfects in 10 to 60 minutes.
Hydrogen peroxide 3% can kill some viruses and bacteria by 10 minutes. An addition hour may be needed for others.
Rubbing alcohol should be left for 10 minutes or longer.
Don’t Just Push the Virus Around
Running a rag back and forth over the surface before the cleaning solution has had time to work, is the wrong strategy. Spray the cleaning solution on and leave it alone. If the solution dries before you can get to it, respray, leave for a few and then wipe down. Or, wipe with a damp cloth and then put into the laundry.
It doesn’t work as well if you spray and immediately wipe away. You may wipe some of the virus or bacteria onto the rag, but you won’t kill the majority on the surface you’re trying to clean.
It was estimated in this study (https://onlinelibrary.wiley.com/doi/full/10.1111/risa.13438), that regular and appropriate hand washing could decrease transmission of viruses in airports by 24 to 69%.
Many other studies have found similar results. From elementary schools to hospitals, appropriate and regular handwashing decreases transmission rates of both viral and bacterial infections.
Regularly clean the hard surfaces of your home—especially if you are not able to completely shelter at home.
Regularly wash soft surfaces—bedding, clothing, cleaning cloths, towels and hand towels.
Cleaning surfaces help to decrease our exposure to a virus (decrease viral load).
To learn how to increase your body’s immune system response, begin by decreasing sugar and processed food intake (Good Carb, Bad Carb), and increasing your phytonutrient intake (The Therapeutic Power of Plants).
Feel free to share your own cleaning strategies or ask questions in the comments below!
Praying for Peace in Christ for you and your family during this time.