The antibacterial soaps, laundry detergents and other household cleaning products that have become increasingly popular in recent years apparently offer little protection against the most common germs, the first major test in people's homes has found.
In a carefully designed study involving 238 Manhattan families, those who used only antibacterial cleaners for about a year were just as likely to get fevers, sniffles, sore throats, coughs, rashes and stomach problems as those who used standard cleaners.
"This study certainly indicates that antibacterial soaps may not be necessary and may not be offering any value," said Elaine L. Larson, associate dean for research at the Columbia University School of Nursing, who led the study. "The very small amount of antibacterial ingredients in these soaps don't seem to be doing much."
Public concern about germs has increased in recent years with highly publicized cases of food poisoning from E. coli, "flesh-eating" bacteria and the emergence of new diseases such as severe acute respiratory syndrome (SARS). More than two-thirds of liquid soaps found on the shelves of U.S. stores now contain antibacterial agents, making it a $16 billion-a-year industry.
Their widespread use has raised concerns that the products could contribute to a dangerous increase in "superbugs" invulnerable to treatment in serious medical situations. The effectiveness of antibacterials has also been questioned because most common infections, such as colds and flu, are caused by viruses that are not affected by antibacterial preparations.
The new study represents the first time scientists have attempted a study to evaluate the products under real-life, day-to-day conditions in homes.
Larson and her colleagues delivered free monthly supplies of general cleaning solutions, laundry detergent and hand soaps to families living near Columbia in New York City. Half the families got supplies containing antibacterial agents while the other half received regular products. Neither the volunteers nor the researchers knew which products an individual family was getting. The researchers also called each family weekly, visited them monthly and conducted extensive interviews every three months to gather detailed data on their cleaning practices and whether family members developed any infections.
Over the course of about a year, the most common symptoms reported were coughs and runny noses, followed by sore throats and fevers, then vomiting and diarrhea, and finally rashes and eye problems. But there was no difference between those using the antibacterial agents and those who were not, the researchers reported today in the Annals of Internal Medicine.
The findings were immediately criticized by groups representing manufacturers of the products, saying numerous other studies have found that the cleaners protect people against infections. The manufacturers said the new study failed to find a benefit primarily because most of the symptoms reported in the study are usually caused by viruses, not the bacteria that the products are designed to fight.
"These products do provide an extra measure of protection from infectious disease," said Richard Sedlak, vice president for technical and international affairs at the Soap and Detergent Association, a trade association.
Larson agreed that most of the symptoms that the participants in the study reported are usually caused by viruses.
"That's the point -- most infections . . . are viral," she said. "So since we don't have a big risk of bacterial infections, then why do we need 72 percent of our liquid soap in this country containing antibacterial ingredients?"
Even for symptoms that often are caused by bacteria -- vomiting and diarrhea -- the study failed to find any indication that the products cut the risk, she added. "There were no differences in those rates, either," she said.
In addition to possibly promoting the evolution of dangerous superbugs, using antibacterial products in the home might make children more likely to develop allergies and asthma, said Stuart Levy, a professor of molecular biology, microbiology and medicine at the Tufts University School of Medicine.
"I have been concerned for a long time about changing the microbiology of the home," said Levy, who was not involved in the new study. "Infants growing up in the home need to be exposed to certain types of bacteria to get their immune systems to mature properly. Too hygienic means that you are more likely to come down with allergies and asthma."
In an accompanying editorial in the journal, J. Todd Weber and James M. Hughes of the National Center for Infectious Diseases at the federal Centers for Disease Control and Prevention said infectious diseases do pose an important public health threat, but the findings are a reminder that the best protection against germs is basic cleanliness.
"Perhaps the frequent admonitions we heard as children are more valid now more than ever -- cover your mouth when you cough or sneeze and wash your hands!" they wrote.
source: http://www.washingtonpost.com/ac2/wp-dyn/A20715-2004Mar1?language=printer 2mar04
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