It might as well be urban legend that some parents successfully shield their children from every possible exposure to germs — only to watch them grow into adults who are utterly defenseless against the slightest bug.

But in these days of barely checked global migration, it’s no wonder we worry about the threat posed to our kids by Ebola, by MRSA, and now by the Zika virus.

Manufacturers smell our fear. Their response is to produce a myriad of products that claim to kill bacteria, viruses, and other germs we didn’t even know were there. But not only are such products overkill in many cases (many germs, such as the trillions in our digestive systems, are essential) — some can cause problems of their own.

A new study about the Dyson Airblade hand dryers used in many public restrooms, for example, shows they spread significantly more germs than regular dryers or paper towels. In fact, they spread 60 times more viruses than regular dryers and 1,300 times more viruses than regular paper towels, said the study, published in the Journal of Applied Microbiology.

And Triclosan, the active ingredient of many anti-bacterial soaps and cleansers, has been ebbing from the market amid health concerns, including the concern that whatever isn’t killed by chemicals can actually grow stronger (hence, the mighty superbug). Other products can lull us into a false sense of security, when all we really need to do is engage in some good old-fashioned hand washing throughout the day.

With that in mind, here is a sampling of other products to … reflect upon.

'Handle' with Care
A public bathroom handle that kills germs left by slobs who don’t wash on their way out sounds like a win-win. Conceived by two students, the ultra-hygienic door handle has an LED that emits ultraviolet light, and the handle is coated with titanium dioxide. The two work together to kill germs. Best of all, the inventors believe the product should cost only about $13. What's not to like?

First, studies have shown that some bacteria, including strains of E.coli, tend to resist UV irradiation. Second, some people who enter the bathroom might get spooked by a weirdly glowing handle … and use a paper towel to touch it. Which, of course, negates the need in the first place for a germicidal handle.

Something to Sneeze At
Colds and flu tend to spread through the household no matter what you do, but the Kleenex Anti-Viral Tissue claims to kill 99.9 percent of these viruses within 15 minutes, thanks to a "moisture-activated middle layer."

Think about this. Blow your nose with one of these, and nearly all the germs that soak through the tissue’s outer layer will die once they reach that middle layer — about 14 minutes and 50 seconds after you’ve tossed the tissue out, at which point it doesn’t matter. Either way, you still have to wash your hands to avoid getting the rest of your family sick.

No Cleaner for the Pump?
Dettol, which makes the $22 No Touch Hand Wash System, says your soap pump is full of germs, and the no-touch system ensures that you won’t need to touch that soap pump. The system "automatically senses hands and dispenses soap to kill 99.9 percent of bacteria and remove viruses," says one product description. But if you're about to wash your hands anyway, what does it matter if you have to touch the soap pump an instant before the soap does its work? We might rise for the bait if the pump killed the other .1 percent of germs, too.

The Ultraviolet Blues
Got allergies? If you’ve tried everything else but can't keep from sneezing, an air purifier can give you some relief. The same can go for filtering tobacco smoke.

But if your air purifier also kills germs, that's worth a few bucks more, right?

Well ... consider that two competing forces are at work. First, ultraviolet light zaps the germs as they pass by; a treated plate attracts the little corpses like a magnet. The UV needs only one thing — that the germs linger long enough to cook them. But the job of the air purifier’s fan is to propel air through the machine as fast as possible, which is too fast for the UV. The same fan that sucks in the germs blows them back out again.

And Their Little Germs, Too
Nobody likes it when insects — flying, crawling, or hopping — make their way into the house. But if you listen to some companies, it's not enough to spray what you can't step on or swat. That pest, after all, leaves behind a cavalcade of germs, and presumably they're harmful, too.

The Home Pest Plus Germ Killer Indoor & Outdoor Insect Killer from Bayer therefore begs the question: Where does it stop? Don't the germs the bugs are carrying host their own smaller germs, and don't those germs carry germs, too — and so on, right down to the unicellular level?

And when, you might ask yourself, was the last time your pediatrician told you that if you'd only given that swatter a good bleach rubdown after taking out that fly, your child's temperature wouldn't be 102?

Foil Hat Not Included
You might also see germ-zapping products in the form of battery-powered UV wands. Hold a wand over a surface — no concerns about exposure time here — and it's supposed to kill bacteria, viruses, dust-mite eggs, fleas, and lice in 10 seconds.

Think about all those doorknobs, faucet and fridge handles, hand towels, magazines … the list is endless. And this is a problem. Even if it works, you won’t use it for long. If your colleagues at work don't make you feel ridiculous as you bathe every surface a hand might possibly have touched, your family will. Mercilessly.

Squeezing By
Hand sanitizers are everywhere, and it's tempting for parents to spritz their kids’ hands with a little sanitizer rather than walk and walk to the nearest bathroom. But they're not perfect alternatives to washing. If there's visible dirt on your hands, you'll mostly smear it around. And the fragrances in these could contain phthalates, some of which are health concerns, and some sanitizers still contain triclosan. Most sanitizers are more than 60 percent ethyl alcohol (120 proof), and they don't have child-proof lids — which has made for some ER visits.

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