Couples Study in Haiti Shows Reduction in Heterosexual HIV Transmission
A study in Haiti of "discordant" heterosexual couples -- those in which one partner is HIV-infected and the other uninfected -- found that almost half of sexually active couples receiving counseling and free condoms adopted safe sex practices (either abstinence or consistent condom use), according to investigators supported in part by the National Institute of Allergy and Infectious Diseases (NIAID). The rate of new HIV infections among couples who consistently used condoms was one-seventh as high as those who did not.
The new findings are reported in the Aug. 15, 1996 Annals of Internal Medicine by Marie-Marcelle Deschamps, M.D., Jean William Pape, M.D., Alice Hafner, M.S., and Warren D. Johnson Jr., M.D., all currently associated with Cornell University Medical College in New York City.
These findings are significant, the researchers say, because they provide insights into the factors associated with heterosexual HIV transmission in a broad population, and suggest approaches to preventing such transmission. Most previous studies of heterosexual HIV transmission have examined high-risk populations such as commercial sex workers and their clients, or patients at sexually transmitted disease clinics.
"Worldwide, the vast majority of people with HIV became infected during heterosexual intercourse, often in the context of a stable partnership," says Dr. Johnson, the B.H. Kean Professor of Tropical Medicine and chief of the Division of International Medicine and Infectious Diseases at Cornell. "This study shows that interventions such as testing, counseling and providing condoms can be highly effective in preventing the spread of HIV between individuals in heterosexual couples. Other recent data have clearly demonstrated that these relatively 'low-tech' interventions can dramatically reduce rates of heterosexual HIV transmission in high-risk groups, as well." (See, for example, New England Journal of Medicine, Aug. 1, 1996, for a discussion by NIAID-supported researchers of HIV risk reduction among Thai soldiers.)
Despite the best efforts of the investigators in Haiti, a large proportion of study participants continued to have unsafe sex and many became infected with HIV. "This finding underscores the importance of research into other means of HIV prevention, including vaccines and microbe-killing gels or creams that women can use before sex to protect themselves from HIV and other sexually transmitted diseases," says Mark Grabowsky, M.D., MPH, chief medical officer for international research in NIAID's Division of AIDS. These and other approaches to HIV prevention are actively being pursued by NIAID-supported investigators in the United States and abroad.
In the current study, investigators of the Group Haitians d'Etude du Sarcome de Kaposi et des Infections Opportunistes (GHESKIO) at the National Institute for Laboratory Research in Port-au-Prince, Haiti, and collaborators from Cornell enrolled 475 HIV-infected patients and their uninfected regular sex partners. Because the early stages of the HIV epidemic in Haiti predominantly affected men, most of the HIV-infected patients (81 percent) were male.
Study physicians informed all volunteers and their sexual partners of their HIV status and evaluated them at three- to six-month intervals for the presence of HIV infection and other sexually transmitted diseases. During their clinic visits, the participants were also queried about their sexual practices (including condom use) and other risk factors for acquiring HIV. All participants received free HIV risk-reduction counseling as well as free latex condoms throughout the study period.
Of the 475 couples who entered the study, 63 percent (298) discontinued sexual activity within six months; some of this was because the partners were ill with AIDS. The remaining 37 percent (177) were sexually active during all or part of the study period, and followed for a median of 20 months. Of these volunteers who were sexually active for at least six months, 45 percent adopted safe sex practices or became abstinent. The percentage of these couples who always used condoms increased from 0 to 24 percent.
The investigators observed a seroconversion rate of 1.0 per 100 person years for couples who always used a condom, and 6.8 per 100 person years for couples who used condoms irregularly or not at all. The seroconversion rates were similar between couples who never used condoms and those who used them irregularly, underscoring the importance of consistent, correct condom use. The female-to-male rate of HIV transmission was 7.6 per 100 person years; the rate of male-to-female transmission was 4.8 per 100 person years.
The investigators confirmed previous reports that other sexually transmitted diseases significantly increase a person's risk of becoming infected with HIV. Genital ulcer diseases, syphilis, and vaginal or penile discharge in the HIV-negative partner, and syphilis in the HIV-infected partner each increased the risk of HIV transmission.
"These findings add to accumulating data that preventing and treating other sexually transmitted diseases, especially those that damage the genital mucosa, may have an important role in minimizing the risk of sexual transmission of HIV," says Dr. Grabowsky. NIAID is currently assessing the usefulness of an aggressive STD control program in preventing HIV transmission in 11,000 men and women in the Rakai district of Uganda.
The high retention rate in the study in Haiti, achieved in a stable population that was receptive to HIV prevention efforts, as well as a persistent rate of infection in the study participants, suggests that discordant couples may be a suitable population for testing other prevention efforts, including efficacy trials of HIV vaccines, Dr. Grabowsky notes.
NIAID is a component of the National Institutes of Health (NIH). NIAID conducts and supports research to prevent, diagnose and treat illnesses such as HIV and other sexually transmitted diseases, tuberculosis, asthma and allergies. NIH is an agency of the Public Health Service, U.S. Department of Health and Human Services.
Deschamps M-M, et al. Heterosexual transmission of HIV in Haiti. Ann Intern Med 1996;125:324-330.