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2.2. How effective are condoms? (AIDS)




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This article is from the AIDS FAQ, by Dan Greening with numerous contributions by others.

2.2. How effective are condoms? (AIDS)

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 sexually transmitted diseases,
including HIV infection.

When condoms are used reliably, they have been shown to prevent
pregnancy up to 98 percent of the time among couples using them as
their only method of contraception. Similarly, numerous studies among
sexually active people have demonstrated that a properly used latex
condom provides a high degree of protection against a variety of
sexually transmitted diseases, including HIV infection.

Condoms are classified as medical devices and are regulated by the
Food and Drug Administration. Each latex condom manufactured in the
United States is tested for defects, including holes, before it is
packaged, and several studies clearly show that condom breakage rates
in this country are less than 2 percent. Even when condoms do break,
one study showed that more than half of such breaks occurred prior to
ejaculation.

Update: Barrier Protection against Sexual Diseases - CDC National AIDS
Clearinghouse

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.

..............................

 

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