Brass "touchless" doorway hooks (or keys) pop up all over the internet with a simple pitch: use them instead of your fingers to open doors and punch keys to protect yourself from bacteria. Brass is an alloy of copper and usually zinc, and copper has antimicrobial properties. So will it protect you from bacteria and more importantly, COVID-19? Probably not, and here's why.
Copper Does Microbial Properties
The first thing to know is that copper really has antimicrobial properties. That is why you will find brass that is used on frequent contact items such as door handles and pressure plates. But it is not instant bacterial death; It can take as long as two hours for copper to kill a wide range of harmful microbes.
We have known copper antimicrobial properties for centuries, and the EPA has tested it thoroughly against several viruses and bacterial types, including E. coli, Staphylococcus aureus (MRSA), influenza A virus, and even fungi. Depending on the purity of the copper, the results were quite outstanding, with a death ratio of 99.99% within 2 hours.
We haven't tested it against SARS-CoV-2
But that doesn't mean copper kills all types of bacteria and viruses. The number of bacteria we have tested is much smaller than the strains of viruses, bacteria and fungi found in the real world.
We have not tested it carefully against SARS-CoV-2, the virus that causes COVID-19. Without that testing, we cannot be sure that it works at all against SARS-CoV-2, and it might not. Even the Copper Development Association, a nonprofit task to secure the right public claims on copper, says as much in an official statement on its website. Officially, EPA only allows claims against six types of bacteria (not viruses).
In early tests, some studies have shown that copper can be effective against SARS-CoV-2 in 4 hours, which is twice as much as other bacteria and viruses that we have tested. But we still need more tests to know for sure.
Copper does not prevent cross contamination and requires cleaning
In each statement about copper antimicrobial properties, you will find two accompanying details that mean a lot to brass hooks. Dirty copper does not kill microorganisms as efficiently and copper does not prevent cross-contamination. Here is the copper development association's version of it:
Laboratory tests show that, when cleaned regularly, uncoated copper alloy surfaces kill> 99.9% of the following bacteria within 2 hours of exposure: MRSA, VRE, Staphylococcus aureus, Enterobacter aerogenes, Pseudomonas aeruges coli O157: H7. Copper surfaces are a complement to and do not replace standard infection control methods and have been shown to reduce microbial contamination, but do not necessarily prevent cross-contamination or infections; users must continue to follow all current infection control methods.
Note the "regular cleaning" and "does not necessarily prevent cross-contamination" parts of the statement.
You will see what is implied in almost all brass marketing keys if you look closely. Usually, the terminology is somewhat in line with "with regular cleaning and proper handling." Without cleaning, copper becomes less effective at killing microbes. Or rather, a dirt and dirt barrier is built up that prevents copper from killing bacteria.
The more you handle your brass or copper wrench without cleaning it, the worse you get it for — Killing bacteria. And given that it can take hours for copper to do its job, if you use a hook to open a door, slide it into your pocket and then slide your hand into your pocket to get it back – you've probably defeated the point completely. Copper can deposit bacteria before it kills them.
That is why most manufacturers of brass hooks show the units hanging in a belt loop or key chain. But even that is not a perfect solution; You have to be diligent to not touch the part of the hook that touches a door or PIN, or not to brush your hand against the part of your pants that contacts your brass hook.
How do you clean copper? It depends on what made it dirty and how sanitary you want to make the hook. But according to Copper Alloy Stewardship "standard hospital cleaners are compatible with antimicrobial copper materials …" but you must be careful to use anything that does not leave the surface "waxed, painted, varnished, varnished, or otherwise coated "It goes back to disrupting the interaction between copper and bacteria.
And of course, if the brass hook you buy turns out to be brass plated, you run the risk of damaging the brass while you clean it, thus destroying any chance of killing bacteria.
So what should you do?
You may be wondering if brass hooks are not the magic bullet to protect you from bacteria, what can you do? Unfortunately, there is not a simple magic bullet. EPA has a list of disinfectants that are effective against SARS-CoV-2, but you are likely to find them with a deficiency.
As the CDC suggests, the best thing you can do is to wash your hands carefully, and avoid touching your face and nose when you're out in public. Wearing a mask can not only help protect you from infection, but it can also help with the goal of not touching your face. It is, after all, a physical barrier.
Even if you use a tool like a brass hook, you still have to wash your hands early and often. Did you handle the brass hook to open a door? Wash your hands anyway. And specifically, you need to do it for at least 20 seconds with warm water and soap.
If you want the perfect version of washing your hands, you can go beyond singing your birthday twice and following the World Health Organization (WHO) protocol. Google will help you with that if you ask.
And of course, besides good hygiene, self-insulation is a good defense against infection. The more people you meet, the higher your risk of exposure. Conversely, you also avoid the risk of exposure by avoiding people. And if you're still not sure, check out reputable sites like CDC and NIH for more information.
But in the end, $ 20 spent on soap and warm water is a safer bet to protect you from infection than a brass hook filled with vague but just within the limits of legal promises.