Self-Decontaminating Hand Sanitizer for Coronavirus

[Hip]

One major route of transmission of the SARS-CoV-2 coronavirus is via touching your mouth, nose or eyes after your hands have been in contact with a virally-contaminated surface.

Thus washing your hands when you get home is important, and in addition, when you are out and about, applying an alcohol hand sanitizer every hour or two is a good idea. But during an average day, an individual comes into contact with 300 surfaces every 30 minutes. Ref: 1 And one study found that on average, people touch their face every 3 minutes.

So even if you regularly use a hand sanitizer every hour, there are still many opportunities for viral contamination on a surface to be transferred to your face via your hands.



So I started thinking in terms of a persistent hand sanitizer, which would destroy any coronavirus contamination picked up on the hands even hours after the sanitizer is applied.

I came across povidone-iodine, which may work for this purpose: this paper surveys disinfectants for coronavirus, and says that povidone-iodine solution at just 0.23% is sufficient to destroy SARS and MERS coronaviruses within 15 seconds to 1 minute (see table 2), when coronavirus particles are placed in suspension in that solution.

Furthermore, unlike alcohol which only disinfects the hands there and then, applying povidone-iodine to the hands appears to have a persistent antimicrobial action, which can last for 6 hours (at least with respect to bacteria, but I could not find data for viruses). Ref: 1

10% povidone-iodine solution is available online (about £5 for 125 ml). So my idea was if you apply say a 1% or 2% povidone-iodine solution to your hands before you go out, your hands in theory may be self-decontaminating for the next few hours.

Obviously this approach has not been tested, but it's possible it may work.



Note that povidone-iodine is different to regular iodine solutions or tinctures. Regular iodine I expect will deactivate coronavirus at time you apply it, I am not sure if it will have a persistent effect. Whereas iodine is slowly released from povidone-iodine, which I believe may underlie its long-lasting action.

In case you think povidone-iodine may stain your hands brown, in fact I found there is almost no noticeable change in the color of your hands when you apply a 1% or 2% solution.

Even if you use a 10% solution, it only makes your hands look very mildly suntanned brown, but not something that anyone would particularly notice.

With 10% povidone-iodine though, there would be quite a bit of systemic iodine absorption: according to a rough calculation I did: if you applied 1 ml of 10% povidone-iodine solution to the skin, then over the hours you would slowly absorb about 5000 mcg of iodine. Though there are high-dose iodine supplements which are 15,000 mcg per tablet, so that's within an acceptable range.



Another potentially useful persistent hand sanitizer for coronavirus is benzalkonium chloride. The above study found a 0.2% solution was less effective for coronavirus compared to povidone-iodine and alcohol, but nevertheless benzalkonium chloride has a persistent action on hands, lasting for 4 hours. Ref: 1

A similar disinfectant compound called benzethonium chloride is found in grape seed extract liquid supplements such as Citricidal® at around 8%. Ref: 1

 

[Wolfcub]

That's interesting stuff @Hip Thank you. Much better thought-out than the plain alcohol sanitisers.

People will say "wow your hands are so tanned....why is your face so white?"

 

[Mary]

Thanks @Hip! btw, it has taken me an amazingly short time to stop the habit of touching my face, mouth, etc. tbh, I'm surprised at how quickly I've adapted to this! And washing my hands many times a day. Something inside me has taken this to heart.

Most of the on-line supplies I see are 10% povidone=-iodine. It might be an interesting experiment to see whose thyroid health improves (or not!) after using this.

Re the Citricidal - I've used it before for systemic bacterial infections and I think it worked. I think this is a good alternative as well!

 

[Wolfcub]

I also wash down non-permeable items received by deliveries, usually with warm water and washing up liquid (dish soap) in the sink, then dry them before putting them away. Permeable items get put on one side to be opened at a much later date!
Scrub fruit too. (usually handled by others somewhere along the line.)
The povidone-iodine mix or the citricidal may also work for doing this? As a wipe-down?

 

[Hip]

Most of the on-line supplies I see are 10% povidone=-iodine.

Yes, that's what I have, 10% povidone-iodine, but I diluted it down 10:1 with water, to make 1%. The study said even 0.23% povidone-iodine was strong enough to disinfect coronavirus within 15 seconds to a minute, so 1% should be strong enough.

Though if you use stronger solutions than 1%, they might last longer on the hands, providing protection for a longer time.

 

[Hip]

I also wash down non-permeable items received by deliveries, usually with warm water and washing up liquid

I am also disinfecting shop-bought items, using dilute bleach.

The paper above says 0.1% sodium hypochlorite kills SARS coronavirus in 5 minutes. Regular household bleach is 5% sodium hypochlorite, so if you dilute down the bleach by putting one tablespoon (15 ml) in 500 ml of water, you will get a 0.15% solution of sodium hypochlorite, which should work fine.

Soap and water I guess should work too, because it works for cleaning hands, provided you scrub well.

The povidone-iodine mix or the citricidal may also work for doing this? As a wipe-down?

Povidone-iodine should work for cleaning surfaces of food packages, though dilute bleach I think will work out cheaper.

I was previously using isopropyl alcohol for disinfecting food packages, because I happened to have some (it's great for cleaning things, which is why I originally bought it). But the price of isopropyl alcohol has shot up as a result of the pandemic, from its normal price of about £15 for 5 liters to about £80 for 5 liters. So it's a bit too expensive to use at the moment.

 

[junkcrap50]

After applying 1% povidone-iodine to your hands, does drying your hands with a paper towel not rub it all off? Do you use such a small amount that you can rub it dry into your hands? How do you apply it exactly?

 

[Hip]

After applying 1% povidone-iodine to your hands, does drying your hands with a paper towel not rub it all off? Do you just rub your hands together until they are dry? How do you apply it exactly?

I bought some pocket-sized 30 ml plastic spray bottles on eBay, and filled them with 1% povidone-iodine. I spray 4 or 5 sprays (which will be about 0.5 ml) into the palm of my hand, and rub this over my hands. It pretty much dries instantly.

30 ml Spray Bottle

I think it would also be feasible to apply some 1% povidone-iodine solution to your face, on the area around your lips and nose, and perhaps also around the eyes. This may then have a virucidal effect on the face itself, should you accidentally touch your face with contaminated hands.