Antibacterial Hand Sanitizers Do they work?

What started out as an informal classroom experiment at East Tennessee State University has turned up disturbing evidence about some alcohol-based instant hand sanitizers — the antiseptic gels and foams that have become popular as a quick way to disinfect hands when soap and water aren't available.

FOR GENERAL USE Some sanitizers can be a good supplement to soap and water.

Many such sanitizers — whether a brand name or a generic version — work well, and are increasingly found in hallway dispensers in hospitals, schools, day care centers and even atop the gangways of cruise ships as one more safeguard against the hand-to-mouth spread of disease. Several studies from such settings have shown that use of the alcohol-based rubs on hands that aren't visibly soiled seems particularly helpful in curbing the spread of bad stomach and intestinal bugs.

But a study published in this month's issue of the journal Emerging Infectious Diseases found that at least one brand of sanitizer found on store shelves, as well as some recipes for homemade versions circulating on Web sites about crafts or directed at parents, contain significantly less than the 60 percent minimum alcohol concentration that health officials deem necessary to kill most harmful bacteria and viruses.

"What this should say to the consumer is that they need to look carefully at the label before they buy any of these products," said Elaine Larson, professor of pharmaceutical and therapeutic research at Columbia's nursing school. "Check the bottle for active ingredients. It might say ethyl alcohol, ethanol, isopropanol or some other variation, and those are all fine. But make sure that whichever of those alcohols is listed, its concentration is between 60 and 95 percent. Less than that isn't enough."

Scott Reynolds, a specialist in infection control at the James H. Quillen Veterans Affairs Medical Center in Mountain Home, Tenn., discovered the problem inadvertently, in the course of giving a simple demonstration on the merits of hand washing to a friend's class of biology students at nearby East Tennessee State.

Mr. Reynolds had the students place their hands on agar plates of growth medium before and after one of several experimental conditions: rubbing their hands briskly under tap water; sudsing with hospital-grade soap and then rinsing with water; or rubbing their hands with a dollop of one of two types of alcohol-based hand sanitizer. The sanitizers used were a foam version from the hospital that contained 62 percent ethanol, and a gel version Mr. Reynolds's wife bought at a local discount store.

The next day, much to Mr. Reynolds's surprise, the culture plates from hands doused and rubbed with the store-bought gel were covered with clumps of bacteria that had, in some cases, formed a visible outline of the student's handprint on the plate.

Only when he flipped the bottle around to read the label on the back did Mr. Reynolds see that the gel's active ingredient was "40 percent ethyl alcohol."

"Otherwise, it looked like all the rest you see in the store," he said. "Same price. Same claims. Same pump bottle."

In a more formal follow-up study, Mr. Reynolds and two colleagues replicated the results, and confirmed that the lack of sufficient alcohol was to blame. If anything, he said, the faulty gel seemed to mobilize the bacteria, spreading them around the hand instead of killing them.

Allison Aiello, an epidemiologist at the University of Michigan who has studied the use and relative effectiveness of alcohol-based gels and antibacterial soaps by consumers as well as hospital workers, said she wasn't surprised by Mr. Reynolds's results from the low-alcohol sanitizer, but she was concerned to read that such a product was on the market.

"I used to work in a virology lab," Dr. Aiello said, "and we knew — it has been known for decades — that an alcohol concentration under 60 percent won't kill the microbes. It's really frightening to think that there are products out there that contain levels lower than that."

Sometimes much lower. One recipe Mr. Reynolds and his colleagues discovered on the Internet for a bubble gum-scented sanitizer aimed at children called for half a -cup of aloe vera gel and a quarter cup of 99 percent rubbing alcohol, with a bit of fragrance. That translates to a concentration of roughly 33 percent alcohol, Dr. Aiello said.

Since 2002, officials at the Centers for Disease Control and Prevention have recommended that health care workers routinely use high quality alcohol-based gels instead of soap and water on their hands when moving from patient to patient — as long the worker's hands aren't visibly soiled.

Alcohol doesn't cut through grime well, so dirt, blood, feces or other body fluids or soil must be wiped or washed away first, if the alcohol in the sanitizer is to be effective. In such cases, hand washing with soap and water is advised.

In October 2005, a committee appointed by the Food and Drug Administration met to discuss, among other things, whether consumers should also be encouraged to use the alcohol-based hand sanitizers.

Dr. Tammy Lundstrom, representing the nonprofit Association for Professionals in Infection Control and Epidemiology, argued that they should. The committee's decision is expected this month.

"About 60 percent of surgery these days is outpatient," Dr. Lundstrom said last week in a phone interview. "We have so many people caring for ill family members at home. Maybe you're without running water because of a hurricane or blackout, or you've got a bad hip and can't move easily to get to the sink as often as you should to wash your hands. What about after you sneeze in the car, or stop to put in contact lenses?"

In all those cases, she said, alcohol-based hand sanitizers — of the correct formulation — could be a godsend, not to replace soap and water, but as an important supplement.

Dr. Aiello sees even more potential uses in the office. "Studies show that the computer keyboard, the phone receiver, and the desk are worse than the bathroom in terms of micro-organisms," she said. "Washing with plain old soap and water should be your first choice. But if you're stuck between meetings and about to grab lunch at your desk, or just use somebody else's keyboard, using a hand sanitizer before and after could be a really good idea."

How much goop should you use? Vigorously rub all sides of your hands with enough antibacterial hand gel or foam to get them wet, and rub them together until they are dry. If your hands are dry within 10 or 15 seconds, according to the C.D.C. guidelines for health care workers, you haven't used enough.

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By DEBORAH FRANKLIN
Published: March 21, 2006