Science Seen Physicist and Time One author Colin Gillespie helps you understand your world.

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Be Careful What You Wish For

Here is a story that can save you money. It might even save your life.

If we could see all of the organisms that surround us, we would see microbes, billions of them, many kinds of viruses, bacteria, fungi and archaea. Most of them do nothing to us. Some Hughes Simpsons tissue-box could help us. Others, if they get a chance, will chew us up. There’s no useful way to decide what is which. The worst lurk where we would least expect, like phones. We can try (like reclusive genius Howard Hughes) to avoid them but they are pervasive so we are bound to pick them up. There are three ways we can try to control them. Plan One is kill them all. Plan Two is teach our bodies to survive. Plan Three is wash them off.

Plan One—kill them—is the standard plan. We spend billions buying products such as antibacterial surface cleansers or hand soaps with triclosan. They kill microbes found in our homes or on our hands, so their makers claim. (And spend millions to sell the message.) Fact is, real-life testing says they don’t kill most microbes. And testing says that using anti-microbial products doesn’t make us safer and if we’re sick they make us less safe. But marketers don’t really try to make us safer (safer means less money) they try to make us worried. Plan One works for them; it doesn’t work for us.

Plan Two—teach our bodies—uses vaccination. It can work well so it’s useful to understand. Our immune systems depend on quantum physics. Protein molecules on the cell walls of bacteria, fungi and archaea or the coats of viruses have shapes we can compute from orbits of electrons in their atoms. Likewise for molecules in our immune systems. Our immune-system molecules protect us from infection because their shapes fit to the bugs’ molecules’ shapes like keys to locks. Pathologists may take days to identify a pathogenic microbe. Thanks to quantum physics our T-cells identify it in milliseconds. But first they must be exposed to that same lock-shape so that they can learn to recognize it; in other words, so they carry a key that fits. There are two ways to achieve this: catch the bug itself and take our chances, or vaccination; a no-brainer choice in my book. The good news is we have vaccines for a dozen common viruses and ten bacteria. The bad news is the Swiss Institute of Bioinformatics lists 129 viruses that infect humans. And more than 50 bacterial infectious species are widespread. More of both are less well known. So Plan Two works for us but has its limits.

Plan Three is: Wash often with soap and water. Its big advantage is that we can take it into our own hands. Its big disadvantage is: Like it or not, Plan Three is in our hands so, if we don’t do it, it does not get done. Our hands pick up infections and, one way or another, move them into us. The physics of Plan Three is simple: Soap (or its synthetic equivalent, detergent) takes over bonds that hold dirt and bugs on your hands. It makes them water-friendly. For example, Harvard Medical School says:

Plain old soap and water is still a good way to clean your hands. In studies, washing hands with soap and water for 15 seconds … reduces bacterial counts by about 90%. When another 15 seconds is added, bacterial counts drop by close to 99.9%.

Only 99.9%? What of the 0.1%, of which we are sure to take in a few? This is where we should be careful what we wish for. Here’s a way to see this: The news says deadly ZARZ has struck your city. There is no vaccine. What is your objective? Zero bugs? You can’t sustain it. Your objective should be to avoid a sudden shot of ZARZ that your immune system can’t handle but use slow exposure to build immunity.

Plan Three does not do much for marketers but it does good things for us. It offers fast (and cheap) protection from those microbes; we don’t pass them around; our bodies learn resistance over time; and healthy workers boost the economy. But, to get the benefits, we’ve got to wash!


Other Reading:

State Government of Victoria (2015, “Anti-bacterial Cleaning Products” ), Better Health Channel,

Image Source:Wes Archer (1993), The Simpsons,

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