 |
| 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
"[email protected]".
.................................................................
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.
|