Clinical Briefs

With Comments from Russell H. Greenfield, MD

Antibacterial Soaps and Infectious Disease

Source: Larson EL, et al. Effect of antibacterial home cleaning and handwashing products on infectious disease symptoms. Ann Intern Med 2004;140:321-329.

Goal: To evaluate the effect of antibacterial cleaning products and soaps on the household incidence of infectious disease symptoms.

Design: Randomized, double-blind trial.

Subjects: Two hundred thirty-eight primarily Hispanic, inner-city households of three or more inhabitants, of whom at least one was a pre-school age child (224 households completed the entire study).

Methods: Households were randomly assigned to use of handwashing and household cleaning products either with or without antibacterial ingredients for a total of 48 weeks. During an initial home visit, baseline data concerning symptoms of infectious disease and home hygiene practices were collected. Home visits were then made monthly, during which time adherence to protocol was assessed through weight of remaining product, and a search for the presence of other cleaning products. Phone contact was made weekly, and home hygiene was assessed quarterly via completion of a lengthy questionnaire. The development of infectious disease symptoms was to be reported with a phone call by a member of the household to their interviewer, or during the weekly phone follow-up.

Results: No statistically significant difference between treatment groups with respect to rates of infectious disease symptoms was found, even when subgroup analyses were considered (reportable symptoms included runny nose, cough, fever, vomiting, diarrhea, conjunctivitis, or boils). The most commonly encountered symptoms were compatible with upper respiratory tract infections.

Conclusion: Use of antibacterial products in the home does not reduce the risk for development of symptoms of infectious disease among generally healthy people.

Study strengths: Duration of intervention and level of follow-up, including repeated household visits.

Study weaknesses: Strong possibility of differing household cleaning and hygienic practices was dismissed; self-reporting of symptoms; weight of residual product offered as surrogate for adherence to protocol; lack of generalizability.

Of note: The products employed had similar formulation save for the presence or absence of an antibacterial ingredient (for example triclosan in liquid handwashing soap, kitchen spray containing quaternary ammonium compounds, or hypochlorite in laundry detergent); both groups received the same liquid dishwashing detergent and bar soap, neither of which contained antibacterial ingredients; all products were delivered monthly and provided free of charge to study participants; the majority of household members were age 19 years or younger; 12.1% of household members had known chronic illness.

We knew that: The majority of outpatient visits made for symptoms of infectious disease are due to upper respiratory tract infections; 75% of liquid and 29% of bar soaps available in the United States contain antibacterial ingredients; data from developing countries suggest a strong association between risk of infection and low prevalence of handwashing; hospitalized patients and people with atopic dermatitis do appear to benefit from the use of antibacterial soaps; risk of promoting antiseptic or antibacterial resistance through the use of antibacterial products, while concerning, remains theoretical.

Clinical import: Health care practitioners will not be surprised to learn that antibacterial products in the home were shown to have little impact on the development of symptoms of viral infectious disease. Still, the authors are quick to point out that results of their study do not preclude a possible effect of reducing symptoms of bacterial disease. With most U.S. residents possessing antibacterial cleaning products in the home, it seems remarkable that manufacturers’ advertised benefits of these agents had, until now, not been put to the test. Acknowledging this study’s shortcomings, otherwise healthy consumers should be advised regarding the lack of significant benefit ascribed to the use antibacterial products in the home, and directed toward less costly alternatives.

What to do with this article: Keep a copy on your computer.

Dr. Greenfield, Medical Director, Carolinas Integrative Health Carolinas HealthCare System Charlotte, NC, is Executive Editor of Alternative Medicine Alert.