A practical guide for the home
Overview
First off, there are plenty of other useful sources out there that explain the importance of washing your hands and how to wash your hands correctly, so this paper will not cover this; but please wash your hands correctly, for 20 seconds and often! Instead, this paper will cover other aspects of managing the spread of SARs-CoV-2, that I personally believe [next to hand washing, our first line of defence] are the most effective ways to combat the spread of CoVid-19*. At the end of this article, there is also a recipe for homemade hand sanitiser with a final concentration of 83.12% alcohol.
(*Please note, I am not a doctor, nor am I a medical professional but I am a scientist (published in peer review) I have a B.Env.Sci (Hons) and I am currently seeking supervisor for a PhD that focuses on zoonotic risk factors of human malaria. I have extensive knowledge of infection dynamics and pathogen control, especially parasites both botanical and blood. I am also highly skilled at both conducting a search of, as well as interpreting peer-review scientific literature, particularly literature in the biosciences and biomedical sciences, including virology. The following information you are being provided with is correct for its time and is the best information available to scientists at this time).
Disinfecting surfaces to prevent the spread of CoVid-19
What you should use
I am writing this guide in response to an in-depth review paper recently published by Kampf and Steinmann (2020), which demonstrates what surface disinfections are likely to inactivate SARs-CoV-2 using model pathogens that are most like SARs-CoV-2 and therefore more than likely can be used to prevent the spread of CoVid-19 (see table 1 below or table 2 of the article). To inactivate the virus on surfaces [number of active versus inactive virion/single virus particles] in the shortest and therefore most effective time frame possible, you need pure rubbing alcohol, 95% ethanol (which is simply methylated spirits) or failing that at least 71% or higher isopropyl alcohol (which Aussies can buy at Bunnings or hardware stores).
The review by Kampf and Steinmann (2020) indicate, both isopropyl alcohol and ethanol (methylated spirits) with a concentration that is >70% (greater than) will inactivate the virus in 30 seconds. Unfortunately, the commercially bought product Isocol is only 64%, so it’s also ineffective for this time frame, but see the tables below to see other time frames to use on less frequented surfaces of the home. Thus this is where good old ‘metho’, for us Aussies saves the day. Therefore the study indicates that you should use these products to wipe down surfaces, making sure to saturate the surface, so it doesn’t evaporate too quickly. It is really important to make sure the alcohol doesn’t evaporate before the time it takes to inactivate the virus, this means you really need to wet/saturate the surface, so don’t forget!
What you shouldn’t use
I’m only going to say this once, do not use the following. Do not use benzalkonium chloride or chlorhexidine, (the main ingredients in disinfectant or disinfectant wipes) unless they have concentrations of at least 0.1% and they will be hard to come by at this stage now anyway! It’s funny (in a morbid way) everyone who panic bought disinfectant wipes have no idea that these products do not kill the virus- they are in fact wasting their time! This is because most disinfectant wipes are only 0.04% benzalkonium chloride, or 0.02% chlorhexidine, so in fact, it can take up to 10 minutes to kill it when used on surfaces. So unless the surface is literally wet and saturated for 10 minutes, it is still contaminated!
Put simply, I wouldn’t even use them if I were you, the risk is too high! It’s a gamble we can’t afford to make. Even more shocking, is that if these concentrations are even less than 0.04% such as 0.01% then forget it, these concentrations do not work at all! In fact, it will take 3 days to kill the virus (the same time it takes for the virus to die anyway!) so don’t use them, it is giving you a dangerous, false sense of security and it is the literal equivalent to doing nothing! Additionally, if you want to know how long the virus survives on surfaces, the paper also outlines how long the virus survives on different surfaces i.e. clothes, paper, steel etc… (see table 2 below or table 1 of the paper).
It is important to understand your hands (whilst organic) are also considered a ‘surface’ so in the event of an emergency (such as if you know you have directly come into contact with someone who is infected) you can ‘disinfect’ your hands or other parts of your body. So you can essentially submerge your hands in methylated spirits (95% ethanol) or 100% isopropyl alcohol for at least 30 seconds, and it will reduce the viral load to what is known as undetectable/safe levels. Basically, you’ll reduce it to nothing. However, the catch with that is, that it will dry out your hands! So best to only do this in an emergency, and make sure you use a moisturiser afterwards! Which brings us to my next point…
Hand sanitiser
Now, I spent a bit of time working this out and came up with my own recipe to make it based on the recommendations from WHO [but if there is anyone out there who feels the ratios are wrong then please correct me]. Here is a break-down of why I strongly believe commercial hand sanitisers are probably no-where near as effective as they are believed to be! A lot of doctors and medical professionals are saying you need a hand sanitiser that is at least 60% this is completely incorrect, it’s actually 70% when it comes to SARs-CoV-2, (see Kampf and Steinmann 2020). Why are doctors saying 60%? Because these professionals are misinformed and they have NOT read the latest studies in peer review! Peer review, for anyone who doesn’t know, is basically the latest up to date knowledge in the sciences that other scientists (usually experts) have agreed and approved to.
The science of peer review is moving really fast at the moment. Unfortunately, it is becoming increasingly apparent to me, that more often than not, doctors and health workers DO NOT read peer review and so they are NOT up to date up with the latest scientific studies, which is critical in times like a global pandemic! How do I know this? Well because every up to date peer-review study I read, does not reflect knowledge or advice given to the public. In fact, according to Kampf and Steinmann (2020) concentrations of alcohol at 70% is not even really that effective against SARs-Cov-2 at all! Yes, it will reduce the viral load but the study demonstrates that with concentrations of 70% the virus only becomes inactive after 10 minutes, and that’s nothing to sneeze at, literally. This means the time it takes for a commercial hand sanitiser to evaporate is probably less than the time it takes to inactivate the virus to safe levels.
This might shock you but…interestingly, as I said earlier, if the concentration of alcohol is >70% it is the most effective. But something really interesting is that if we increase it from 71-75%, then the viral load is reduced to almost nothing, in… wait for it… 30 seconds! So that’s 30 seconds versus 10 minutes, which is obviously a no-brainer! So basically at 70%, you’d need to stick your hand in the hand sanitiser for 10 minutes to really get the full effect! In essence, it’s pretty useless. Whereas we know that with concentrations >70% (table 1) we see a massive reduction in the time it takes to reduce the viral load; and at 75% the viral load is reduced to undetectable levels in just 30 seconds! And here’s the really really interesting thing, most commercially produced sanitisers are a mere 70%, so isn’t it interesting that as soon as the threshold of 70% has been reached, you see a huge jump in the time it takes to reduce the viral load!?
This sort of result I would argue, suggests viruses like SARs-Cov-2 and new strains emerging from it, can develop some sort of resistance to commonly used concentrations of commercially available hand sanitiser and or household disinfectants! However, this may just be an artefact of the fact that products and their concentrations, were designed around studies such as these. Thus, is what lead us to design these effective products in the first place, however, it is a compelling argument to suggest resistance, none the less!
Now if you scroll your finger up to the top of table 2, you’ll notice the higher the concentration of alcohol the better, so theoretically you’d want a hand sanitiser with the highest possible concentration of alcohol, something that reduces the viral load in the shortest possible time frame but also doesn’t evaporate before this time. Kampf and Steinmann (2020) demonstrated saturation of the virus using differing concentrations of alcohol starting at 75-78% right up to 95-100% reduce the viral load to almost nothing in 30 seconds.
So in terms of hand sanitiser you really need something that is >71%, and it just so happens that WHO recommends a final product which is 80%. However, as mentioned earlier, we can’t keep dousing our hands in high concentrations of alcohol, not only will they will dry out but you’ll have to use a lot! Plus to get a high concentration of alcohol in that final product you need a high concentration to begin with. So we need something to both counteract that dryness and keep the concentration of alcohol at an effective level-to reduce the viral load. We don’t want to dilute it past the point of its effectiveness. To do this, we need to dilute it by adding an emollient which will counteract that dryness but also keep it lingering longer. Basically, when you are dealing with alcohol in high concentrations, you need to make sure the dilution factor will be no less than the final concentration that is required to reduce the viral load i.e. must be >71%. Therefore ideally at least 75% for isopropyl alcohol or 78% for ethanol to reach the 30-second mark (see table 1). Obviously, we don’t want to be only slightly better than commercial products, we want to be better! So to ensure the most effective outcome, we need to ensure we start with an initial concentration of 95% so that our final product is at least 80%, as recommended by WHO.
Table 1 Kampf and Steinmann (2020) demonstrate, it is likely that SARs-Cov-2 inactivation is most effective at concentrations of alcohol >70% (yellow) whereas surface disinfectants chlorhexidine and benzalkonium chloride (green) are ineffective at concentrations <0.2%.
Table 2 As demonstrated by Kampf and Steinmann (2020) it is likely that SARs-CoV-2 will follow a similar time frame to other pathogens.
References:
Kampf, G., Todt, D., Pfaender, S., & Steinmann, E. (2020). Persistence of coronaviruses on inanimate surfaces and its inactivation with biocidal agents. Journal of Hospital Infection. [Link to full article] https://www.sciencedirect.com/science/article/pii/S0195670120300463?fbclid=IwAR0WKiJmkj2jvsrbJTe_FeCjFZRfFPAy9T5EHTOw571F-FDP-EdLdTmv8ZA
World Health Organisation https://www.who.int/gpsc/5may/Guide_to_Local_Production.pdf
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N.F.Clark’s home-made hand sanitiser
*Generally speaking to slightly reduce the concentration you must have more alcohol than your solvent/emollient, generally 3 parts alcohol, 1 part the solvent/emollient. Alcohol without solvents are really tough on our hands so adding the glycerin will ensure your hands are quite moisturised and don’t dry out. Please also note that this recipe does not include hydrogen peroxide, since it is not essential to the process*
You will need:
- Ethanol alcohol/methylated spirits 950 ml/L (must be 95% concentration)
- Pure glycerine or glycerol
Ingredients
Methylated spirits (210 ml)
Glycerin (30ml) equiv. 1/8 cup
Method
Pour in 210ml of methylated spirits in a clean, dry glass bowl or jug, then add 30ml of glycerin and stir well. For the equation and for the concentration to work, your final mixture must add up to 240ml. Pour it into a spray or pump bottle and you’re done! You can also double this recipe to make more.
And that’s it, now you have a home-made hand sanitiser that is at least 10% more effective than store bought*, as peer review studies indicate concentrations such as this are far more effective at reducing the viral load than their commercially produced counterparts.
Of course that aside, nothing is more effective than washing your hands; and no hand sanitiser should be used unless in the absence of soap and water!
Chemical equation this recipe is based on: C1V1=C2V2
950×3.5/4 (which is a little bit over 3/4cup) which is the equiv. to 95%x210/240= 83.12% which is also equiv. to… 210ml= 3 quarter cups+ 1/8 of a cup… but since the final product must add up to 240ml; this means to reduce the concentration of ethanol to 83.12% then we need 30 ml of our emollient which is 1/8 of a cup of glycerin.
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When you talk about 60%, 70%, 95% ethanol, you should specify whether you are talking about w/v or v/v. Some of the products in the market that are labelled as less than 70% are actually more than 70% when you convert to the correct units. I note your formulation uses 95% v/v.
As an old pokies addict, on holiday in SA where coins still rule, I have bought a pile of plastic single-use gloves for the use of. On leaving I wash with soap and water before removing the gloves.
I wish to wash my hands of this stupid, terminally evil government of superstitious, pompous, ignorant, misguided, awful, stupid fools, led by a lying fantastical, dogmatic, errant idiot who lives in a world that never ever existed and thus allows anuses to create falsehoods to suit. If you live a lie daily, you are untrustworthy, inferior, untruthful, dishonest and deficient.
Hi,
I have wipes with 0.47% W/W of benzalkonium chloride. I don’t have an understanding of W/W but am assuming that the wipes have less than the required amount to be effective against covid19. I read your article which states percentages without W/W but am assuming the wipes arent ok. Can you confirm this for me. Also could I add methylated spirits to the packets of useless wipes I bought to make them effective? How would I figure out how to do this? Many thanks
Does petrol kill the virus covid 19
This information needs to be made public; we simply cannot afford to gamble with it! It may prevent more spreading as unaware people are relying on useless hand sanitiser thinking its working when its not.
Thank you Nicole for posting this information!
Finally someone who knows chemistry has clarified the use of Australian metho for hand sanitiser!
I have been wanting to make my own WHO recipe hand sanitiser for my family but can’t get a hold of Isopropyl Alcohol so been considering Metho.
But, I’ve been doing my head in with the lack of info regarding what is in Australian metho and whether it contains harmful substances such as methanol or Pyridine, etc…
I will be following your recipe which uses metho.
Thanks heaps!
Two things to say:
(1) This article gives the false impression that this is new research on the current SARS-CoV-2 virus, when in fact it is a summary of all previous available data on SARS-CoV (i.e. that old one from 2002/2003 that caused SARS), MERS-CoV and other coronaviruses. For example, the data in the table you quoted for ethanol and 2-propanol were taken from four papers, dated 1988, 2005, 2005 and 2017 (specifically, the 70% data were from 1988 and 2005). It would be better to clarify that you are just suggesting that similar results might apply to our current virus.
(2) You specifically suggest “at least 71% or higher isopropyl alcohol” in your article, but in the table you quoted, 2-propanol, i.e. isopropyl alcohol, was listed as effective after 30 seconds at 70% concentration on SARS-CoV (again, the 2002/2003 SARS virus, not our current one). Perhaps there was a bit of a mix-up when reading the table for 70% ethanol and 70% 2-propanol? As a corollary, since the 75% data is for 2-propanol only, the argument that if you raised the concentration from 70% to 71%~75%, the virus is killed far more quickly, isn’t valid.
Hi Apple Pie (the author of the article here)
You are quite right it is not new research that is why I have specifically said it is a review and why I have stated that model organisms are where we draw our conclusions. In science a ‘review’ is considered a review of literature (not a new study) readers will see that when they consult the table as they will see that the study does not examine SARs-Cov-2, thus there can be no confusion.
Likewise, no where have I claimed the study is absolutely indicative of SARs-CoV-2, but in science model organisms are considered to be ‘just as good’ for drawing conclusions, however as with anything a margin of error may exist but unfortunately this cannot be avoided. Model organisms are standard practice in science, many models are analogous to the real thing which was why I used the language ‘it is likely that SARs-Cov-2…. similar language used by the authors of the study. Additionally, members of Coronaviridae whilst different, all contain the same type of protein in their capsid meaning oxidation (which is the break down of these proteins by denaturing them in an alcohol solution) and likely only differs by a small margin. Additionally we now know that the genome of SARs-CoV-2 is 80% similar to SARs-CoV, so in all likely hood ‘inactivation time’ is not likely to differ too wildly when compared to other strains either.
Please remember that the table is not mine it is a direct cut-out from the study and therefore I can only draw from the results shown. You also mentioned ‘perhaps there was a bit of a mix-up when reading the table for 70% ethanol and 70% 2-propanol?’, no there was no mix up.
Allow me to clear this up for you because you’ve missed quite a lot, see where it says in the 6th column ‘reduction of viral infectivity?’ these are a measure of log reductions, the higher the log reduction the greater the effectiveness of the solution. As you can see, for 2-propanol after 30 seconds, at 70%, SARs-Cov has a log reduction of 3.3, whereas at concentrations >70% i.e 75% it has a log reduction of 4, therefore solutions of 2-propanol are likely to be far more effective at concentrations well above 70%, hence my reason for stating this.
Note also that the log reduction for 2-propanol versus the log reduction for ethanol (>70%) is not the same, as they do not display the same trend? This is because unlike with ethanol where the greater the concentration the greater the log reduction, 2-propanol becomes less effective as these concentrations increase, e.g. 70% 2-propanol is no more effective than 100% 2-propanol.Thus for concentrations of alcohol (>70%), ethanol is far more effective, as the effectiveness of 2-propanol is caped at 75%, whereas ethanol continues to trend upwards, and since there is no 75% it is correct to just state ethanol at concentrations >70% are more effective at reducing the viral load than 2-propanol at concentrations of >70%; the reason being that 2-propanol becomes less effective as concentrations increase. Unfortunately we can’t know when such a decrease begins, but in all likely hood, the data are indicating it is not likely to be as effective as ethanol at 78%.
These might seem like trivial differences, but such a deficit could be the difference between inactivation of a few hundred thousand virions versus a few million. Since this article is written for the laymen,I feel my initial explanation is sufficient wherein there is no need for spurious accuracy or an in-depth explanation of log reduction parameters.
Thanks for the info Nicole,
I have been using a solution of isopropyl alcohol with a dash of hydrogen peroxide to help cut through the cellular membrane, but I shall now be switching to metho-base (+peroxide) and adding a dab of glycerole to soften the skin-scour.
Ps beauty wam!
As a committed heroin addict, before sharing a fix I always ensure to slip a condom over the end of the needle.
Pps, as an etymological nerd, I am bemused by the way that ‘quarantine’ (forty day isolation) has trend-shifted to become the default word for a mere 14 day exclusion period without the corresponding linguistic shift identifying such relatively brief isolation as a mere ‘quatorzine’.
Then again, why be specific when referring to crucial safety measures against the gestation of deadly pathogens?
Anyways, back to my 40 day pan-oceanic cruise.
Am currently awaiting my ordered luncheon of macaque-brain tartare in fruitbat sauce.
Bon appetite.
Thanks for posting this Nicole.
I have concerns with regards to the safety of using Methylated Spirits on ones skin.
In particular, the risk of exposure to denaturants such as Methanol, Pyridine, etc…
I understand some to be very toxic and can be absorbed through the skin.
I haven’t been able to find a source that clarifies exactly what is used for Australian metho. Some Googling indicates Methanol is not used as much in Australia anymore but may still be used albeit in less concentration. Some googling indicates only Bitrex is used. It certainly hasn’t been clear on any of the packaging of Methylated spirits that I’ve ever purchased nor is it clear on manufacturers websites.
I understand that commercially produced hand sanitisers use “denatured alcohol”, one just needs to look at the ingredients on the back. However, what exactly this “denatured alcohol” is, is not clear and obviously one cannot assume it’s metho.
I wonder if there is a denaturing standard used in Australia that all manufacturers must follow.
Are you able to confirm whether Australian made Methylated Spirits is safe for skin application specifically for the purpose of a hand sanitiser?
Hi everyone, rest assured that domestic methylated spirits no longer contain methanol, I believe this source https://www.rch.org.au/clinicalguide/guideline_index/Ethanol_Posioning/ is enough to conclusively state this. Additionally Digger methylated spirits which you can buy at woolies (not sure about Coles) specifically states that it contains 95% ethanol and 5% water, you can find this on their product information sheets on their website: https://diggersaustralia.com.au/safety-data-sheets/. Additionally it would be a serious health risk if you purchased a product that did not explicitly state that it contained methanol, so if it says 95% ethanol as the ingredients on the bottle, there’s a good chance it doesn’t contain methanol simply because it hasn’t stated it. I would imagine this would be considered more dangerous not to notify the purchaser given that methanol deaths have occurred relatively recently so here is another source of interest ( I haven’t had a chance look at this source yet) https://ww2.health.wa.gov.au/~/media/Files/Corporate/general%20documents/Clinical%20coding/Index%20coding%20rules/WACR-031820.pdf. If in doubt, pick up some Diggers metho or make a quick call to the supplier of a product you have in question. Hope everyone is fairing well during this time and if you have any more questions, please let me know. You can also find me on Facebook easily enough, as I am more likely to respond to messages there much quicker :).
Hi Lynett,
Studies demonstrate that even concentrations of Benzalkonium chloride which are at 0.2% even after 10 minutes is ineffective (that would also be assuming the surface has been saturated for a full 10 minutes) given that fact and the trends displayed in the data it would be risky to assume that a slight increase to 0.4% is any different. In fact the study specifically states it does Benzalkonium chloride does not inactivate the virus. I would not risk it to combat the spread of SARs-CoV-2, however Benzalkonium chloride is excellent at deactivating the virus Norovirus (stomach bugs) at just 0.04% and therefore is not without it’s use when it comes to preventing the spread of gastro. Hope that helps 🙂
Hi Doctor Soup, rest assured that as per the recipe, the ethanol is expressed in v/v%, rather than confuse my readers I decided to leave this part out, but I did state ‘the mixture must add up to 240ml. As far as I can tell the same units of measurements have been used by the authors of the study, presumably to make sure translation and replication of studies are universal in nature, I cannot imagine they would deviate from the standard, and v/v% is generally the assumed ratios when mixing liquids together. Hence only water would have been added to dilute alcohol thus it’s safe to assume they used v/v% as they only mixed 2 liquids together. Additionally anyone who purchases ethanol or mythelated spirits with 95% ethanol will see that it contains v/v on the bottle and we can assume the solution added (glycerol) is also 100% in nature thus v/v%. Hope this clears things up for you,
Nicole 🙂
Hi everyone, I did a little more digging and it appears Coles brand methylated spirits also DOES NOT contain methanol, here is the product information sheet: https://www.coles.com.au/~/media/files/coles/pdfs/msds/household/coles-smart-buy-methylated-spirits-1-litre.pdf it’s increasingly UNLIKELY that any metho in Australia is likely to contain methanol.
Australian methylated spirits contains no methanol. It has additives to make it taste utterly foul to deter all but the most desperate folk from drinking it.
Methanol is extremely toxic to humans.
As a diabetic 1, not 2, am insulin dependant and have for years used Isocol to put on cottonbud to clean etc diabetic items (used
for pricking fingers)
This Isocol (brand) has 640ml/L isopropyl alcohol, hence assume it is not as effective for Covid 19……..but as have invested in large
bottles of the Isocol brand, do I need to / can I add something ie metho to the Isocol, to make it suitable for using on hands to
kill Covid 19 (the usual Isocol ratio is ok as only use for cleaning diabetic glucose levels items).
Thanking for your expertise as a scientist….the world needs more tertiary science students and appropriate well paid graduate positions!
Hi Rosyln, thank you for your kind words. I really do hope graduate positions and paid PhD positions will open up after all this mess! At the moment there is so little government funding and they are so prestigious, it’s like winning the lottery!
Thanks for your question, it’s a great idea and the answer is yes you can! However you do need to be very specific about the volumes that you use from each of your concentrations of both ethanol and isopropyl, this is because of the difference in the concentrations of both. So rather than guess I consulted a chemist for you, the good news is you can combine them for a better final concentration but the bad news is that because the isopropyl is the alcohol with the least concentration of the two it doesn’t play a big role in the final concentration. The chemist has recommended the following: 80ml of ethanol (95%), 8ml of Isopropyl (64%) and 12ml of glycerin (and it’s very important you stick to this if you want to get your 73% sanitiser in the end. I believe doubling it is not that simple, so I would not recommend it but if it turns out you can then I will come back to you. Stay safe and I hope this helps 🙂
Hi Nicole,
I have contacted Diggers directly regarding the content of their methylated spirits product and have received documentation from Recochem (owners of Diggers) which lists content as follows:
Ethanol – 95% Min
Denaturant (Denatonium Benzoate) – 6.6ppm
Denaturant (Methyl Isobutyl Ketone) – 0.25%
Denaturant (Fluoroscein) – 1ppm
Water – Balance
Recochem did not recommend using their methylated spirits as hand sanitiser.
In regards to the Coles brand metho being 95% ethanol and 5% water, I think these labels are misleading.
This suggests no Denaturant has been used and would therefore be in breach of the Excise Act.
If in fact the product is made up of a 100% ethanol+Water solution it cannot possibly be Methylated Spirits (Denatured Alcohol).
I noticed the link to the specification PDF is not currently available at the Coles website.
It might be worth pointing out that the main point of Denatured Alcohol in Australia is so that an Ethanol based product can be provided for purposes other than human consumption (such as industrial, cleaning, manufacturing, etc…) but at a lower cost.
But to do this the product must be denatured to deter human consumption and avoid the Excise associated with alcoholic beverages.
According to the Schedule listed on the ATO website the list of approved denaturants includes some very toxic chemicals including methanol.
https://www.ato.gov.au/law/view/document?DocID=ELD/ED201610/00001&PiT=99991231235958
I have decided to skip methylated spirits and go with isopropyl alcohol which unfortunately is considerably more expensive however the safety of isopropanol is much clearer and the end product still works out to be much cheaper than store bought product.
Thanks.