Soap and Water: A Weapon Against HIV?
December 30, 2003
Editor's note: Soap and water will no doubt prove useful as a tool to reduce HIV transmission in developing countries where condoms are unavailable or negotiation for condom use is impossible. Soap and water is no substitute for proven safer sex methods such as male or female condom use. By reporting this story, STEP is in no way advocating reliance on soap and water to prevent HIV infection. In addition, the diaphragm is not considered an effective barrier to HIV. STEP warmly encourages its readers to use condoms.
Soap and water may prove to be a very effective weapon again HIV. A recent study demonstrated that a bar of soap and tap water mixture decreased HIV viral activation by 30-fold. When soap and water was mixed with washings from a woman's cervix and vagina (CVL) and with seminal fluid (SL) [cum], there was a 57% to 87% decrease in the number of viable peripheral blood mononuclear cells (a type of white blood cell that carries HIV). "The present study demonstrates that soap and water solutions should be effective in inactivating HIV and HIV-infecting cells associated with barrier contraceptives (e.g., diaphragms and female condoms) or cells that are present in the vaginal canal," the researchers conclude.
Dr. Jay A. Levy, coauthor of the report, [said] that "the main message of this research is that regular soap works to kill HIV. Its major use in this regard should be on other instruments, such as diaphragms, used to prevent HIV transmission." Levy emphasized that soap and water should not be used as a douche to eliminate HIV from the vagina. First, this method has not been tested, he stressed. Second, soap can have adverse effects, including disrupting the lining of vagina that might actually make it more susceptible to infection, and altering the normal population of vaginal microbes that can protect against other infections.
Postcoital [after the sex act] genital cleansing with soap and water may be effective in preventing HIV infection, but the direct effect of a soap solution on HIV has not been reported before the results of this study were released. HIV can be inactivated by a variety of chemicals and surfactants as well as by an antimicrobial hand wash product. However, these agents may be irritating to the genital mucosa and difficult to obtain. This report documents the effects of common soap and water on HIV as well as white blood cells, which may also play a key role in HIV transmission.
A commercial bar soap (Ivory) was completely dissolved in warm tap water at several concentrations. For these studies, a diluted solution was used (1 g/1,000 ml) to ascertain possible conditions in the environment. The direct virus-killing action of genital secretions was first measured. Suspensions of virus were then evaluated for infectivity after exposure to an equal volume of soap and tap water, tap water alone, or control medium for 2 to 6 minutes.
When HIV was exposed to control medium, CVL alone, SF alone, or a CVL-SF mixture, no noticeable effect on viral infectivity was noted until the 6 hour time point, when a tenfold decreased infectivity of the virus in CVL was observed. By 12 hours, the CVL had caused a 1,000-fold decrease in virus infectivity. In contrast, HIV in control medium or CVL-SF did not show a tenfold decreased infectivity until 12 hours after incubation, and at 24 hours a 1,000-fold dilution of virus still resulted in a productive infection.
Exposure of HIV to soap and water for 2 to 6 minutes decreased viral infectivity by more than 1,000-fold. When the virus was in a CVL-SF mixture, the virucidal activity of the 1-g/1,000 ml soap and water mixture was completely eliminated. However, with a 1-g/200 ml soap solution, viral infection was reduced by more than 30-fold after either 2 or 6 min of exposure.
In addition to the widespread use of soap solutions to clean female barrier contraceptives after their removal from the vaginal canal, several recent studies have indicated that the practice of vaginal cleansing with soap, detergents, or disinfectants is common in the developing world. The present study demonstrates that soap and water solutions should be effective in inactivating HIV and HIV-infected cells associated with barrier contraceptives or cells that are present in the vaginal canal. For these experiments, Ivory bar soap was chosen because of its relatively simple ingredients and its accessibility to women internationally. However, soap and water needs to be further evaluated for its effects on the vaginal [bacteria] if used as a douche in conjunction with female barrier contraceptives. In addition, in developing countries, access to clean water is imperative for these simple approaches to be effective in preventing HIV transmission.
The information in this article was modified from the original study report. For access to the entire study, including methods, please note the following citation: Virucidal Efficacy of Soap and Water against HIV in Genital Secretions. Antimicrobial Agents and Chemotherapy, Oct 2003, p. 3321-3322, Vol. 47, No. 10. Jonathan Z. Li, Elizabeth C. Mack, and Jay A. Levy.
This article was provided by Seattle Treatment Education Project. It is a part of the publication STEP Ezine.