CDC NATIONAL AIDS HOTLINE TRAINING BULLETIN #38 - March 30, 1993
Centers for Disease Control and Prevention

In a letter to the editor, "Inactivation of Human Immunodeficiency Virus-1 at Short Time Intervals Using Undiluted Bleach," in the Journal of Acquired Immune Deficiency Syndrome; 6:218-219, February, 1993, Paul Shapshak, et al. state that a 10% bleach solution did not inactivate HIV-1. The Hospital Infections Program of the National Centers for Infectious Diseases at CDC does not feel that this information indicates any need for changing the recommendation to use a 1:100 dilution of household bleach (or 1/4 cup bleach to 1 gallon of tap water) for environmental disinfection of HIV or HBV.

The laboratory methods used in the study included growing HIV in tissue culture and spinning the suspension until pellets of HIV-infected cells were formed. The pellets were then exposed to bleach to see if HIV was inactivated. This type of laboratory experiment using concentrated virus does not replicate the biological behavior of HIV in nature and bears no relationship to situations encountered in health-care settings.

Numerous studies have demonstrated that a wide range of chemicals, including bleach at dilutions of much less than 1:100, rapidly inactivate HIV. The data presented in the study do not present evidence that the use of diluted bleach for disinfection of environmental surfaces is inadequate. There is evidence that the use of undiluted or 1:10 dilutions of bleach can mar many environmental surfaces and may also cause respiratory and skin irritation in some individuals. Bleach solutions more concentrated than an approximate 1:100 dilution should not be used routinely.

CAUTION : No other chemical, including detergents, should be added to the bleach and tap water; a rapid evolution of toxic chlorine gas could result from such mixtures.