|Ken Shirriff -> AIDS theories -> Do condoms leak HIV?|
Abstract: Condoms were tested in an in vitro system simulating key physical conditions that can influence viral particle leakage through condoms during actual coitus. The system quantitatively addresses pressure, pH, temperature, surfactant properties, and anatomical geometry. A suspension of fluorescence-labeled, 110-nm polystyrene microspheres models free human immunodeficiency virus (HIV) in semen, and condom leakage is detected spectrofluoro- metrically. Leakage of HIV-sized particles through latex condoms was detectable (P less than 0.03) for as many as 29 of the condoms tested. Worst-case condom barrier effectiveness (fluid transfer prevention), however, is shown to be at least 10(4) times better than not using a condom at all, suggesting that condom use substantially reduces but does not eliminate the risk of HIV transmission.
LEAKING THROUGH LATEX CONDOMS These are answers from the Centers for Disease Control and Prevention (CDC) to questions concerning the possibility of HIV "leaking" through latex condoms. 1. Can HIV leak through microscopic holes in latex condoms? The Food and Drug Administration (FDA) published a study in the July-August 1992 issue of "STD" which examined whether HIV-sized glass beads could be forced through latex condoms under stressful laboratory conditions. These conditions included higher concentrations of the "virus" (glass beads) than in semen, a fluid that doesn't stick together as much as semen, and forces that simulated 10 minutes of thrusting AFTER ejaculation. Most latex condoms leaked absolutely nothing. The worst condom found would still reduce exposure risk by 10,000-fold, i.e., only 1 HIV virus might "leak" through only 1 of every 90 condoms. Other tests have shown that under "normal" conditions, HIV does not pass through a latex condom that is not torn or broken. 2. How often do condoms break? The studies do not agree on an exact rate of breakage. Many studies of condom effectiveness have counted how often women whose partners used condoms for birth control have gotten pregnant. This "failure rate" includes cases where the couple did not use a condom every time they had sex or used the condoms incorrectly. Some studies have included the times the condom was torn accidentally by the people using it. Studies in other countries of breakage caused by defects in the condom itself show a breakage rate ranging from 0% to 7%. In the United States, most studies show the breakage rate is less than 2 out of every 100 condoms, probably less than 1 out of every 100. (Centers for Disease Control and Prevention, HIV/AIDS Prevention Training Bulletin, January 28, 1993.)
Paper copies of the following factsheet are available by calling the CDC National AIDS Hotline at 1-800-342-AIDS or by sending email to "firstname.lastname@example.org". ................................................................. CENTERS FOR DISEASE CONTROL AND PREVENTION HIV/AIDS PREVENTION ................................................................. Facts about ... Condoms and Their Use in Preventing HIV Infection and Other STDs With more than 1 million Americans infected with HIV, most of them through sexual transmission, and an estimated 12 million other sexually transmitted diseases occurring each year in the United States, effective strategies for preventing these diseases are critical. The proper and consistent use of latex condoms when engaging in sexual intercourse--vaginal, anal, or oral--can greatly reduce a person's risk of acquiring or transmitting STDs, including HIV infection. In fact, recent studies provide compelling evidence that latex condoms are highly effective in protecting against HIV infection when used properly for every act of intercourse. Latex condoms are highly effective when used consistently * * * and correctly-- new studies * * * provide additional evidence that condoms work The protection that proper use of latex condoms provides against HIV transmission is most evident from studies of couples in which one member is infected with HIV and the other is not, i.e., "discordant couples." In a study of discordant couples in Europe, among 123 couples who reported consistent condom use, none of the uninfected partners became infected. In contrast, among the 122 couples who used condoms inconsistently, 12 of the uninfected partners became infected. As these studies indicate, condoms must be used consistently and correctly to provide maximum protection. Consistent use means using a condom from start to finish with each act of intercourse. Correct condom use should include the following steps: * Use a new condom for each act of intercourse. * Put on the condom as soon as erection occurs and before any sexual contact (vaginal, anal, or oral). * Hold the tip of the condom and unroll it onto the erect penis, leaving space at the tip of the condom, yet ensuring that no air is trapped in the condom's tip. * Adequate lubrication is important, but use only water-based lubricants, such as glycerine or lubricating jellies (which can be purchased at any pharmacy). Oil-based lubricants, such as petroleum jelly, cold cream, hand lotion, or baby oil, can weaken the condom. * Withdraw from the partner immediately after ejaculation, holding the condom firmly to keep it from slipping off. MYTHS ABOUT CONDOMS There continues to be misinformation and misunderstanding about condom effectiveness. The Centers for Disease Control and Prevention (CDC) provides the following updated information to address some common myths about condoms. This information is based on findings from recent epidemiologic, laboratory, and clinical studies. Myth #1: Condoms don't work Some persons have expressed concern about studies that report failure rates among couples using condoms for pregnancy prevention. Analysis of these studies indicates that the large range of efficacy rates is related to incorrect or inconsistent use. The fact is: latex condoms are highly effective for pregnancy prevention, but only when they are used properly. Research indicates that only 30 to 60 percent of men who claim to use condoms for contraception actually use them for every act of intercourse. Further, even people who use condoms every time may not use them correctly. Incorrect use contributes to the possibility that the condom could leak from the base or break. Myth #2: HIV can pass through condoms A commonly held misperception is that latex condoms contain "holes" that allow passage of HIV. Although this may be true for natural membrane condoms, laboratory studies show that intact latex condoms provide a continuous barrier to microorganisms, including HIV, as well as sperm. Myth #3: Condoms frequently break Another area of concern expressed by some is about the quality of latex condoms. Condoms are classified as medical devices and are regulated by the FDA. Every latex condom manufactured in the United States is tested for defects before it is packaged. During the manufacturing process, condoms are double-dipped in latex and undergo stringent quality control procedures. Several studies clearly show that condom breakage rates in this country are less than 2 percent. Most of the breakage is due to incorrect usage rather than poor condom quality. Using oil-based lubricants can weaken latex, causing the condom to break. In addition, condoms can be weakened by exposure to heat or sunlight or by age, or they can be torn by teeth or fingernails. PREVENTING HIV INFECTION AND OTHER STDS Recommended Prevention Strategies Abstaining from sexual activity is the most effective HIV prevention strategy. However, for individuals who choose to be sexually active, the following are highly effective: * Engaging in sexual activities that do not involve vaginal, anal, or oral intercourse * Having intercourse only with one uninfected partner * Using latex condoms correctly from start to finish with each act of intercourse Other HIV Prevention Strategies - Condoms for Women The FDA recently approved a female condom, which will soon be available in the United States. A limited study of this condom as a contraceptive indicates a failure rate of about 26 percent in 1 year. Although laboratory studies indicate that the device serves as a mechanical barrier to viruses, further clinical research is necessary to determine its effectiveness in preventing transmission of HIV. - Spermicides The role of spermicides in preventing HIV infection is uncertain. Condoms lubricated with spermicides are not likely to be more effective than condoms used with other water-based lubricants. Spermicides added to the tip of the condom are also not likely to add protection against HIV. - Making Responsible Choices In summary, sexually transmitted diseases, including HIV infection, are preventable, and individuals have several responsible prevention strategies to choose from. But the effectiveness of each one depends largely on the individual. Those who practice abstinence as a prevention strategy will find it effective only if they always abstain. Similarly, those who choose any of the other recommended prevention strategies, including condoms, will find them highly effective if used correctly and consistently. For further information contact: CDC National AIDS Hotline: 1-800-342-AIDS Spanish: 1-800-342-SIDA Deaf: 1-800-324-7889 CDC National AIDS Clearinghouse P.O. Box 6003 Rockville, MD 20849-6003 ________________________________ Condoms and STD/HIV Prevention July 30, 1993
Subject: MMWR 42(30): 08/06/93 Following is the final electronic text from the Morbidity and Mortality Weekly Report (MMWR), vol. 42, no. 30, dated August 6, 1993. The MMWR is published by the U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention (CDC). Inquiries about the MMWR Series, including material to be considered for publication, should be directed to: Editor, MMWR Series, Mailstop C-08, Centers for Disease Control and Prevention, Atlanta, GA 30333; telephone (404) 332-4555. ------------------------------------------------------------------------ Acting Director, Centers for Disease Control and Prevention Walter R. Dowdle, Ph.D. Acting Director, Epidemiology Program Office Barbara R. Holloway, M.P.H. Editor, MMWR Series Richard A. Goodman, M.D., M.P.H. Managing Editor, MMWR (weekly) Karen L. Foster, M.A. Writers-Editors, MMWR (weekly) David C. Johnson Patricia A. McGee Darlene D. Rumph Caran R. Wilbanks ------------------------------------------------------------------------ CONTENTS OF THIS ISSUE: 1. Update: Barrier Protection Against HIV Infection and Other Sexually Transmitted Diseases 2. Nosocomial Enterococci Resistant to Vancomycin -- United States, 1989-1993 ------------------------------------------------------------------------ Update: Barrier Protection Against HIV Infection and Other Sexually Transmitted Diseases Although refraining from intercourse with infected partners remains the most effective strategy for preventing human immunodeficiency virus (HIV) infection and other sexually transmitted diseases (STDs), the Public Health Service also has recommended condom use as part of its strategy. Since CDC summarized the effectiveness of condom use in preventing HIV infection and other STDs in 1988 (1), additional information has become available, and the Food and Drug Administration has approved a polyurethane "female condom." This report updates laboratory and epidemiologic information regarding the effectiveness of condoms in preventing HIV infection and other STDs and the role of spermicides used adjunctively with condoms.* Two reviews summarizing the use of latex condoms among serodiscordant heterosexual couples (i.e., in which one partner is HIV positive and the other HIV negative) indicated that using latex condoms substantially reduces the risk for HIV transmission (2,3). In addition, two subsequent studies of serodiscordant couples confirmed this finding and emphasized the importance of consistent (i.e., use of a condom with each act of intercourse) and correct condom use (4,5). In one study of serodiscordant couples, none of 123 partners who used condoms consistently seroconverted; in comparison, 12 (10%) of 122 seronegative partners who used condoms inconsistently became infected (4). In another study of serodiscordant couples (with seronegative female partners of HIV-infected men), three (2%) of 171 consistent condom users seroconverted, compared with eight (15%) of 55 inconsistent condom users. When person-years at risk were considered, the rate for HIV transmission among couples reporting consistent condom use was 1.1 per 100 person-years of observation, compared with 9.7 among inconsistent users (5). Condom use reduces the risk for gonorrhea, herpes simplex virus (HSV) infection, genital ulcers, and pelvic inflammatory disease (2). In addition, intact latex condoms provide a continuous mechanical barrier to HIV, HSV, hepatitis B virus (HBV), Chlamydia trachomatis, and Neisseria gonorrhoeae (2). A recent laboratory study (6) indicated that latex condoms are an effective mechanical barrier to fluid containing HIV-sized particles. Three prospective studies in developed countries indicated that condoms are unlikely to break or slip during proper use. Reported breakage rates in the studies were 2% or less for vaginal or anal intercourse (2). One study reported complete slippage off the penis during intercourse for one (0.4%) of 237 condoms and complete slippage off the penis during withdrawal for one (0.4%) of 237 condoms (7). Laboratory studies indicate that the female condom (Reality [trademark]**)--a lubricated polyurethane sheath with a ring on each end that is inserted into the vagina--is an effective mechanical barrier to viruses, including HIV. No clinical studies have been completed to define protection from HIV infection or other STDs. However, an evaluation of the female condom's effectiveness in pregnancy prevention was conducted during a 6-month period for 147 women in the United States. The estimated 12-month failure rate for pregnancy prevention among the 147 women was 26%. Of the 86 women who used this condom consistently and correctly, the estimated 12-month failure rate was 11%. Laboratory studies indicate that nonoxynol-9, a nonionic surfactant used as a spermicide, inactivates HIV and other sexually transmitted pathogens. In a cohort study among women, vaginal use of nonoxynol-9 without condoms reduced risk for gonorrhea by 89%; in another cohort study among women, vaginal use of nonoxynol-9 without condoms reduced risk for gonorrhea by 24% and chlamydial infection by 22% (2). No reports indicate that nonoxynol-9 used alone without condoms is effective for preventing sexual transmission of HIV. Furthermore, one randomized controlled trial among prostitutes in Kenya found no protection against HIV infection with use of a vaginal sponge containing a high dose of nonoxynol-9 (2). No studies have shown that nonoxynol-9 used with a condom increases the protection provided by condom use alone against HIV infection. Reported by: Food and Drug Administration. Center for Population Research, National Institute of Child Health and Human Development, National Institutes of Health. Office of the Associate Director for HIV/AIDS; Div of Reproductive Health, National Center for Chronic Disease Prevention and Health Promotion; Div of Sexually Transmitted Diseases and HIV Prevention, National Center for Prevention Svcs; Div of HIV/AIDS, National Center for Infectious Diseases, CDC. Editorial Note: This report indicates that latex condoms are highly effective for preventing HIV infection and other STDs when used consistently and correctly. Condom availability is essential in assuring consistent use. Men and women relying on condoms for prevention of HIV infection or other STDs should carry condoms or have them readily available. Correct use of a latex condom requires 1) using a new condom with each act of intercourse; 2) carefully handling the condom to avoid damaging it with fingernails, teeth, or other sharp objects; 3) putting on the condom after the penis is erect and before any genital contact with the partner; 4) ensuring no air is trapped in the tip of the condom; 5) ensuring adequate lubrication during intercourse, possibly requiring use of exogenous lubricants; 6) using only water-based lubricants (e.g., K-Y jelly [trademark] or glycerine) with latex condoms (oil-based lubricants [e.g., petroleum jelly, shortening, mineral oil, massage oils, body lotions, or cooking oil] that can weaken latex should never be used); and 7) holding the condom firmly against the base of the penis during withdrawal and withdrawing while the penis is still erect to prevent slippage. Condoms should be stored in a cool, dry place out of direct sunlight and should not be used after the expiration date. Condoms in damaged packages or condoms that show obvious signs of deterioration (e.g., brittleness, stickiness, or discoloration) should not be used regardless of their expiration date. Natural-membrane condoms may not offer the same level of protection against sexually transmitted viruses as latex condoms. Unlike latex, natural-membrane condoms have naturally occurring pores that are small enough to prevent passage of sperm but large enough to allow passage of viruses in laboratory studies (2). The effectiveness of spermicides in preventing HIV transmission is unknown. Spermicides used in the vagina may offer some protection against cervical gonorrhea and chlamydia. No data exist to indicate that condoms lubricated with spermicides are more effective than other lubricated condoms in protecting against the transmission of HIV infection and other STDs. Therefore, latex condoms with or without spermicides are recommended. The most effective way to prevent sexual transmission of HIV infection and other STDs is to avoid sexual intercourse with an infected partner. If a person chooses to have sexual intercourse with a partner whose infection status is unknown or who is infected with HIV or other STDs, men should use a new latex condom with each act of intercourse. When a male condom cannot be used, couples should consider using a female condom. Data from the 1988 National Survey of Family Growth underscore the importance of consistent and correct use of contraceptive methods in pregnancy prevention (8). For example, the typical failure rate during the first year of use was 8% for oral contraceptives, 15% for male condoms, and 26% for periodic abstinence. In comparison, persons who always abstain will have a zero failure rate, women who always use oral contraceptives will have a near-zero (0.1%) failure rate, and consistent male condom users will have a 2% failure rate (9). For prevention of HIV infection and STDs, as with pregnancy prevention, consistent and correct use is crucial. The determinants of proper condom use are complex and incompletely understood. Better understanding of both individual and societal factors will contribute to prevention efforts that support persons in reducing their risks for infection. Prevention messages must highlight the importance of consistent and correct condom use (10). References 1. CDC. Condoms for prevention of sexually transmitted diseases. MMWR 1988;37:133-7. 2. Cates W, Stone KM. Family planning, sexually transmitted diseases, and contraceptive choice: a literature update. Fam Plann Perspect 1992;24:75-84. 3. Weller SC. A meta-analysis of condom effectiveness in reducing sexually transmitted HIV. Soc Sci Med 1993;1635-44. 4. DeVincenzi I, European Study Group on Heterosexual Transmission of HIV. Heterosexual transmission of HIV in a European cohort of couples [Abstract no. WS-CO2-1]. Vol 1. IXth International Conference on AIDS/IVth STD World Congress. Berlin, June 9, 1993:83. 5. Saracco A, Musicco M, Nicolosi A, et al. Man-to-woman sexual transmission of HIV: longitudinal study of 343 steady partners of infected men. J Acquir Immune Defic Syndr 1993;6:497-502. 6. Carey RF, Herman WA, Retta SM, Rinaldi JE, Herman BA, Athey TW. Effectiveness of latex condoms as a barrier to human immunodeficiency virus-sized particles under conditions of simulated use. Sex Transm Dis 1992;19:230-4. 7. Trussell JE, Warner DL, Hatcher R. Condom performance during vaginal intercourse: comparison of Trojan-Enz (trademark) and Tactylon (trademark) condoms. Contraception 1992;45:11-9. 8. Jones EF, Forrest JD. Contraceptive failure rates based on the 1988 NSFG. Fam Plann Perspect 1992;24:12-9. 9. Trussell J, Hatcher RA, Cates W, Stewart FH, Kost K. Contraceptive failure in the United States: an update. Stud Fam Plann 1990;21:51-4. 10. Roper WL, Peterson HB, Curran JW. Commentary: condoms and HIV/STD prevention--clarifying the message. Am J Public Health 1993;83:501-3. *Single copies of this report will be available free until August 6, 1994, from the CDC National AIDS Clearinghouse, P.O. Box 6003, Rockville, MD 20849-6003; telephone (800) 458-5231. **Use of trade names is for identification only and does not imply endorsement by the Public Health Service or the U.S. Department of Health and Human Services.