There was a time, not long ago, when squirting gelatinous goo into your hands after every cough and before every meal would have seemed absurd. No more. Thanks to the flu pandemic, hand sanitizer has made its way into nearly every home, office, and school.
Alex Wong/Getty Images
What's in your bottle, Anne Schuchat?
What's in your bottle, Anne Schuchat? Alex Wong/Getty Images
The germ-killing ingredient in most of the stuff is alcohol. Any product that is more than 60 percent alcohol quickly punches holes in the membranes of most harmful bacteria and viruses (including H1N1) and quickly "kills them dead," as the insecticide ads say, without damaging the skin. But what about the versions sold as "alcohol-free?" Do they work?
"Depends on what's in them," says Allison Aiello, an epidemiologist at the University of Michigan who has studied hand hygiene.
Several years ago, Aiello looked into the safety and effectiveness of various antibacterial soaps and hand sanitizers for an FDA advisory panel (start here, go to p53). The alcohol-based products did the best job in all the studies she reviewed, she says. That's why she, the CDC, and other public health experts encourage their use when you can't get to soap and water. The CDC actually has published a chart comparing the effectiveness of various "hand-hygiene antiseptic agents."
Gels containing "quaternary ammonium compounds" (benzalkonium chloride is the best known) work against most worrisome germs too, Aiello says. But — unlike the alcohol-based sanitizers — they leave a residue on the skin that at least one study has hinted could foster antibiotic resistance.
What about "thymus vulgaris oil" or other products that advertise themselves as safer and just as effective as the alcohol-based sanitizers?
"I'd be very skeptical," says Dr. William Schaffner, an infectious disease researcher at Vanderbilt University Medical center.
There's also a slew of products that make claims that FDA says are bogus. You can check the FDA's list of "fraudulent 2009 H1N1 Influenza Products," but remember that the list isn't exhaustive.
Also remember, alcohol-based sanitizers can't cut through dirt and grime, nor are they likely to kill one particularly nasty gut bug, C. difficile. Best protection of all, Schaffner says, "Wash your hands frequently with soap and water."