Researchers at Columbia University gave anti-bacterial cleaning products to 120 New York City families, monitored them for almost a year, and found they experienced about the same number of runny noses, sore throats and fevers as another group that got regular soaps and detergents.
The study, published in Tuesday's edition of the Annals of Internal Medicine, concluded that the products did not reduce the risk for symptoms of the viral infections that are among the most common causes of colds, coughs and stomachaches.
The study's lead author, Elaine Larson, said the results would not surprise physicians; the products tested were designed to kill bacteria, not viruses.
But that may not be as clear to the average consumer, she said.
"People think, in their heads, that if they use an anti-bacterial soap, it will keep them from getting an infection," Larson said. "What we found is that these products don't offer much added value."
The study did not say if the soaps were effective in reducing bacterial infections.
Brian Sansoni, a spokesman for the Soap and Detergent Association, a group that represents soap makers, said consumers should not misinterpret the study as saying that anti-bacterial products are worthless.
"It's important to remember that the products that were tested here do not make anti-viral claims," he said.
Sansoni said other studies have shown that anti-bacterial soaps and household cleaning products are effective in killing organisms that cause a variety of illnesses, including skin infections and food poisoning.
The growing use of anti-bacterial soaps in the home has been of concern to some scientists who theorize that their widespread use might lead to the evolution of harder-to-kill, antibiotic-resistant germs.
In all, 1,178 people from a poor, predominantly Hispanic neighborhood in Manhattan participated in the study.
By David B. Caruso