Update: Barrier Protection against Sexual 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 ( (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.