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Two public health agencies are recommending that the contraceptive
spermicide nonoxynol-9 (N-9) should not be used as a means of HIV
protection among high-risk women.
The Centers for Disease Control and Prevention (CDC) in the United
States and the Geneva-based Joint United Nations Programme on HIV/AIDS
(UNAIDS) recently recommended that women should not use N-9 spermicides to
prevent HIV transmission. CDC also recommends that N-9 should not be used
as a protective barrier against HIV transmission during anal intercourse.1
This means providers should discontinue counseling individuals who
cannot use a condom to consider N-9 spermicides for HIV prevention.
Providers should inform condom users that using an N-9 lubricated condom
is better than using no condom at all, but N-9 may not offer any
additional protection against HIV. Condoms without N-9 may be a better
option for HIV prevention.
The recommendations reflect the implications of a recent study by
UNAIDS and the U.S.-based Columbia Laboratories. In that study,
preliminary data suggested that N-9 was not effective against HIV
infection and may have facilitated HIV transmission. Both the CDC and
UNAIDS continue to review their public health guidelines for the use of
N-9 for HIV prevention and for pregnancy prevention in populations at high
risk for HIV.
The UNAIDS-sponsored study, conducted among 991 prostitutes in Benin,
South Africa, Thailand and Côte d'Ivoire, showed that a low-dose (52.5
mg) N-9 gel was significantly less effective in protecting women from HIV
than the placebo, a vaginal moisturizer called Replens. All women were
given HIV counseling, provided with condoms and encouraged to have their
partners use condoms. Nevertheless, 59 of 500 women using the N9 gel
acquired HIV, compared with 41 of 500 women in the placebo group. Women
exposed to N-9 spermicide were also more likely to have genital lesions,
thought to increase risk of HIV acquisition.2
"We know N-9 is not the answer [to HIV prevention] -- so we need
to continue the search" for an effective microbicide to prevent HIV
transmission, says Dr. Joseph Perriëns, head of the UNAIDS microbicide
effort.
Meanwhile, individuals need to know that a male latex condom used every
time they have vaginal, oral or anal sex is the most effective way to
reduce the risk of sexually transmitted infections (STIs), including HIV.
They should use a condom during sex if they have any of the following risk
factors: they have a new sex partner, or their partner has sex with
another person; they or their partner gets any STI or HIV/AIDS; or, they
or their partner share drug injection needles with others.
Unanswered questions
"Given the results of the UNAIDS trial, people are appropriately
cautious," says Dr. Penelope Hitchcock in the United States, chief of
the Sexually Transmitted Diseases Branch of the U.S. National Institute of
Allergy and Infectious Diseases (NIAID). "It is clear that N-9 can
irritate the vagina and we are increasingly aware that vaginal lesions
have the potential to make women vulnerable to HIV infection."
Although an earlier FHI study in Cameroon showed no difference in HIV
transmission rates among women using a low-dose (72 mg) N-9 vaginal
contraceptive film and women receiving a placebo film, rates of genital
lesions among women who used N-9 were greater than among women using
placebo.3 In another study, use of a contraceptive sponge
containing 1,000 mg N-9 was associated with increased incidence of both
genital ulcers and HIV infection.4
However, some experts have not abandoned hope for N-9 as a
prophylactic. First, they point out, more women using N-9 in the UNAIDS
trial may have acquired HIV than women using the vaginal moisturizer
placebo because the moisturizer itself may have had a protective effect.
Preventing the vagina from becoming dry may have reduced vaginal trauma
and lesions during intercourse.
Also, the UNAIDS trial data need further, closer analysis. "Only a
preliminary analysis of the UNAIDS trial data has been made public,"
says Dr. Hitchcock. For example, scientists have not analyzed the degree
of exposure to N9 by women who became HIV-infected.
N-9 spermicides might still be shown to protect against HIV among women
who use the product infrequently. The vaginal irritation or ulceration
caused by N-9 is related to the N-9 concentration per dose and frequency
of use, with lower concentration and less frequent use causing less or no
irritation or ulceration.5
All studies of N-9 spermicide effectiveness against HIV transmission
have been conducted among high-risk commercial sex workers. Conducting
such trials has been considered essential "in order to get an answer
in a reasonable time among a reasonable number of people," says Dr.
Hitchcock. "We must do studies in high-risk populations where use of
the test product possibly holds the highest benefit, as well as possibly
the highest risk. The dilemma is that the results of a trial among
high-risk women who use the product often may not be indicative of how
well the product protects low-risk women who might use it far less
often." Infrequent exposure to N-9 spermicide, for example, is less
likely to lead to vaginal irritation than exposure to it several times a
day.
Results from trials conducted among commercial sex workers are also
difficult to interpret because of the sexual practices of these women,
says Dr. Zeda Rosenberg of FHI, scientific director of the HIV Prevention
Trials Network (HPTN), a research project involving FHI and other
organizations to evaluate HIV prevention interventions, including
experimental microbicides. "While commercial sex workers may be
successful in negotiating condom and microbicide use with their
clients," she says, "they tend not to use these products with
their primary partners. Thus, while working, they may develop condom or
microbicide-related vaginal irritation that increases their risk of HIV
infection when they have unprotected sex with an infected primary
partner."
For these reasons, testing the effectiveness of N-9 as a microbicide
against HIV among women who use the product infrequently but are still at
high risk of infection "would be useful," says Dr. Rosenberg.
Status of N-9 trials
Due to safety concerns, FHI and the other organizations involved in
HPTN have discontinued testing N-9 as an agent for HIV prevention. A
proposed HPTN study of a high-dose (100 mg) N-9 gel among some 4,500
HIV-negative women in Malawi and Zimbabwe will not proceed as planned.
An N-9 study in Cameroon by the Care and Health Program, a
nongovernmental agency, and FHI evaluated the effectiveness of high-dose
(100 mg) N-9 gel against male-to-female transmission of gonorrhea and
chlamydia among 1,000 high-risk women. (The use of N-9 spermicide among
volunteers in the study was nearly completed when the UNAIDS trial results
were released.) There is no evidence that N-9 used relatively
infrequently, as it was in this study, increases risk of HIV infection.
Meanwhile, FHI is conducting a randomized, controlled U.S. study to
evaluate further the contraceptive efficacy and consistency of use of N-9
spermicide products in various doses and formulations. This trial involves
women who are at low risk for HIV, unlike the high-risk study population
in the UNAIDS study. Also, participants in the efficacy study are
monogamous. "Nevertheless, we feel that it is appropriate to inform
women in our trial about the UNAIDS trial results," says Dr.
Elizabeth Raymond of FHI, an obstetrician-gynecologist who is the study's
principal investigator. "For women who are currently enrolled, we
have issued a fact sheet informing them of the results and stressing the
need to take precautions in situations of high risk for STI/HIV infection.
For future participants, we have modified the existing informed consent
form to include more information about spermicides and HIV."
Concerns raised by the UNAIDS study have fueled a sense of urgency to
test experimental microbicidal candidates. Several products currently in
advanced safety testing in women could proceed more quickly to combined
safety and efficacy evaluation.
All microbicidal agents under scrutiny for advanced efficacy testing
are unlikely to cause the vaginal irritation associated with N-9. Some of
them are noncontraceptive. "This is very important," says Dr.
Hitchcock, "since women throughout the world need a way to get
pregnant without running the risk of becoming infected with HIV."
-- Kim Best
References
- Gayle HD. Notice to readers: CDC statement on study
results of product containing nonoxynol-9. MMWR 2000;49(31):717-18.
- Van Damme L, Laga M. Vaginal microbicides, an
update. The XIII World Conference on HIV/AIDS, Durban, South
Africa, July 9-14, 2000.
- Roddy RE, Zekeng L, Ryan KA, et al. A controlled
trial of nonoxynol 9 film to reduce male-to-female transmission of
sexually transmitted diseases. N Engl J Med 1998;339(8):504-10.
- Kreiss J, Ngugi E, Holmes KK, et al. Efficacy of
nonoxynol-9 contraceptive sponge use in preventing heterosexual
acquisition of HIV in Nairobi prostitutes. JAMA 1992;268(4):477-82.
- Roddy RE, Cordero M, Cordero C, et al. A dosing
study of nonoxynol-9 and genital irritation. Int J STD AIDS 1993;4(3):165-70;
Martin HL, Stevens CE, Richardson BA, et al. Safety of a nonoxynol-9
vaginal gel in Kenyan prostitutes: a randomized clinical trial. Sex
Trans Dis 1997;24(5):279-83; Martin HL Jr, Richardson BA, Stevens
CE, et al. Evaluation of a low dose nonoxynol-9 gel for the prevention
of sexually transmitted diseases, Abstract No. 33610. Int Conf AIDS
1998;12:29.
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Anal Intercourse
Presents Serious HIV/STI Risks
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In some cultures, heterosexual anal intercourse has been
practiced for many reasons, including pleasure, curiosity,
preventing pregnancy, preserving virginity or avoiding contact
with menstrual blood.1
Survey data from both developed and developing countries show
that between 10 percent and 50 percent of sexually active
adolescents and adults in the general population have engaged in
heterosexual anal intercourse.2Most of these
individuals do not use condoms to protect themselves from disease.
Having unprotected, receptive anal sex presents more risk of
sexual HIV transmission for women than does unprotected vaginal
intercourse.3It is also associated with anorectal
sexually transmitted infections (STIs), hepatitis B infection and
human papilloma virus (HPV)-related anal lesions and cancer in
women.4
"Not only is the prevalence of this culturally taboo
practice probably underestimated in self-reports from survey data,
but its health risks appear to be severely underestimated by a
substantial proportion of sexually active women and men in North
and Latin America as well as parts of South Asia, Africa, and
other regions," says Dr. Daniel Halperin, assistant professor
at the Center for AIDS Prevention (CAPS) and Medical Anthropology
at the University of California, who has researched the subject.
"The idea that only vaginal HIV transmission causes
heterosexual AIDS is perpetuated by the fact that HIV/STI
prevention programs targeted at the general population do not
specifically address anal sex. This typically stigmatized and
hidden sexual practice should be given greater emphasis in
AIDS/STI prevention, women's care, and other health promotion
programs."
Condoms are typically used less frequently for anal sex than
for vaginal intercourse, he says. In studies conducted in the
developing world, approximately 70 percent to 90 percent of people
engaging in heterosexual anal intercourse report never or
inconsistently using condoms during the practice. The same pattern
of lower condom use for anal sex has been documented in U.S.
studies.5
Lack of protection
Low levels of condom use for heterosexual anal sex are
explained in part by concerns that male condoms are more likely to
break or slip during anal sex than during vaginal sex.
Estimates of condom breakage and slippage rates associated with
anal use are difficult to interpret. But, unless lubricant is
used, anal sex has been associated with a much higher risk of
condom slippage than has vaginal sex.6 Meanwhile,
studies consistently show that individuals with less condom
experience report more condom breakage and slippage,7
and heterosexual women generally have far less experience using
condoms during anal intercourse than vaginal intercourse.
Given these condom-related concerns, researchers are
increasingly interested in whether topical rectal microbicides
might protect against HIV transmission during anal intercourse.
Vaginal use of nonoxynol-9 (N-9) spermicidal products has been
shown to be ineffective against HIV transmission and may even
facilitate it, so anal use of these products is likely to be risky
and is not recommended.8 Researchers from the New
York-based Population Council have also observed in a small study
that rectal use of commercially available lubricants containing
moderate to low dosages of N-9 causes sloughing of extensive areas
of the rectal surface, a situation expected to increase risk for
HIV/STI infection.9
"The results of our study were alarming," says
Population Council senior scientist Dr. David Phillips,
"although more research must be done to confirm them. We
continue to look at N-9 because it remains available and people
are still using it rectally. However, I would not recommend the
rectal use of N-9." Meanwhile, he cautions, other lubricants
marketed for use during anal intercourse are unregulated, untested
and may irritate rectal tissue, at least as much as N-9 does.
-- Kim Best
References
- Halperin DT. Heterosexual anal intercourse:
prevalence, cultural factors, and HIV infection and other
health risks, part I. AIDS Patient Care STDs 1999;13(12):717-30;
Voeller B. AIDS and heterosexual anal intercourse. Arch Sex
Behav 1991;20(3):233-76.
- Laumann EO, Gagnon JH, Michael RT, et al. The
Social Organization of Sexuality: Sexual Practices in the
United States. (Chicago: University of Chicago Press,
1994)98-99,107-9; Hein K, Dell R, Futterman D, et al.
Comparison of HIV+ and HIV- adolescents: risk factors and
psychosocial determinants. Pediatrics 1995;95(1):96-104;
Kotloff K, Tacket C, Wasserman S, et al. A voluntary
serosurvey and behavioral risk assessment for human
immunodeficiency virus infection among college students. Sex
Trans Dis 1991;18(4):223-27; Reinisch J, Hill C, Sanders
S, et al. High-risk sexual behavior at a midwestern
university: a confirmatory survey. Fam Plann Perspect 1995;27(2):79-82;
MacDonald NE, Wells GA, Fisher WA, et al. High-risk STD/HIV
behavior among college students. JAMA 1990;263(23):3155-59;
Melbye M, Biggar R. Interactions between persons at risk for
AIDS and the general population in Denmark. Am J Epidemiol 1992;135(6):593-602;
Cunningham I, Díaz-Esteve C, González-Santiago M, et al.
University students and AIDS: some findings from three surveys
-- 1989, 1990, 1992. Boletín de Estudios Puertorriqueños.
1994;5:44-59; Leal de Santa Inez A. Hábitos e Atitudes
Sexuais dos Brasileiros. (São Paulo: Editora Cultrix,
1983)41.
- Halperin D. Neglected risk factors for
heterosexual HIV infection: anal intercourse, male
circumcision, and dry sex. The XIII International AIDS
Conference, Durban, South Africa, July 9-14, 2000;
European Study Group on Heterosexual Transmission of HIV.
Comparison of female to male and male to female transmission
of HIV in 563 stable couples. BMJ 1992;304(6830):809-13;
Padian N, Shiboski S, Glass S, et al. Heterosexual
transmission of HIV in northern California: results from a
ten-year study. Am J Epidemiol 1997;146(4):350-57.
- Moscicki AB, Hills NK, Shiboski S, et al.
Risk factors for abnormal anal cytology in young heterosexual
women. Cancer Epidemiol Biomarkers Prev 1999;8(2):173-78;
Rosenblum L, Darrow W, Witte J, et al. Sexual practices in the
transmission of hepatitis B virus and prevalence of hepatitis
delta virus infection in female prostitutes in the United
States. JAMA 1992;267(18):2477-81; McMillan A, Young H,
Moyes A. Rectal gonorrhea in homosexual men: source of
infection. Int J STD AIDS 2000;11(5):284-87; Voeller.
- Baldwin JI, Baldwin JD. Heterosexual anal
intercourse: an understudied, high-risk sexual behavior. Arch
Sex Behavior 2000;29(4):357-73; Hein; Halperin DT.
- Smith A, Jolley D, Hocking J, et al. Does
additional lubrication affect condom slippage and breakage? Int
J STD AIDS 1998;9(6):330-35.
- Silverman BG, Gross TP. Use and
effectiveness of condoms during anal intercourse: a review. Sex
Trans Dis 1997;24(1):11-17.
- Gayle HD. Notice to readers: CDC statement
on study results of product containing nonoxynol-9. MMWR 2000;49(31):717-18.
- Phillips DM, Taylor CL, Zacharopoulos V, et
al. N-9 causes exfoliation of sheets of rectal epithelium. Microbicides
2000 Conference. Alexandria, VA, March 13-16, 2000.
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