Condom effectiveness similar for pregnancy/HIV protection
Challenge: Triple global condom use to stem infection spread
Good news: A recent meta-analysis of studies of HIV transmission among "serodiscordant" couples — those who differ in their HIV infection status — suggests that the condom may be about as successful in preventing HIV transmission as it is in protecting against pregnancy.1
However, while more men and women are choosing condoms for pregnancy prevention, protection against HIV/AIDS and other sexually transmitted diseases (STDs), or both, condom use must increase to help stem the spread of HIV/AIDS, say public health officials.
Every day, more than 15,000 people become infected with HIV, and more than 7,000 people die of AIDS, says Ushma Upadhyay, MPH, a researcher in the Baltimore-based Johns Hopkins University (JHU) School of Public Health’s Center for Communication Programs and a co-author of a 1999 report calling for increased accessibility of condoms.2 To evaluate worldwide efforts to promote condoms and to measure how much more effort is needed, JHU researchers compared current to needed use.
"We estimate that total condom use is 6 to 9 billion condoms per year, based on surveys of use," explains Upadhyay. "We also came up with a condom need estimate, the number of condoms needed by married and unmarried men to prevent all unwanted pregnancies and transmission of sexually transmitted diseases."
Twenty-four billion condoms are needed worldwide, concluded researchers, leaving a shortfall of 15 to 18 billion condoms. "These numbers demonstrate that much more work is needed in order to slow the spread of STDs, including HIV/AIDS, and this need is urgent," Upadhyay concludes. "Using a condom is the best way to avoid contracting any STD during sex."
Similar protection found
While the use of condoms has been recommended for individuals who have multiple partners, a primary partner who is HIV-infected, or a partner whose HIV status is unknown, the absolute level of protection has not been accurately established, say researchers at the University of Texas Medical Branch in Galveston.1
The best measure of condom efficacy is obtained by comparing monogamous, serodiscordant couples who always use condoms during intercourse with those who never do, explain the researchers. Because test ethics preclude placing anyone at risk for disease, such couples cannot be randomly assigned to "always use condoms" or "never use condoms" study groups. To obtain estimates of condom effectiveness against HIV, figures must be drawn from observational studies, which may be biased by an unequal distribution of HIV risk factors across study categories, specifically between condom users and nonusers.
In their meta-analysis, the Texas researchers looked at information on condom use and HIV serology from 25 published studies of serodiscordant heterosexual couples. Condom efficacy was calculated from the HIV transmission rates for always-users and never-users.
Consistent use of condoms provides protection from HIV, the researchers conclude. The level of HIV protection from a condom is close to 87%, comparable or slightly lower than its contraceptive efficacy rating. According to Contraceptive Technol ogy, first-year typical use pregnancy probabilities for couples using condoms are 14% for the male condom and 21% for the female condom. Perfect-use rates (where condoms are used consistently and correctly for every act of intercourse) are 3% for male condoms and 5% for female condoms.3
Performing this particular meta-analysis was challenging because the studies had varying periods of observation, notes James Trussell, PhD, professor of economics and public affairs, associate dean of the Woodrow Wilson School of Public and International Affairs, and faculty associate of the Office of Population Research at Princeton (NJ) University. "Most [studies] reported the proportion of initially HIV-negative partners seroconverting in a period of x months," he explains. "But of course, the longer x is, the higher will be the fraction who seroconvert, just as the proportion of women becoming pregnant in one year will exceed the proportion becoming pregnant in one month, even if the monthly rate of pregnancy is constant."
For Susan Weller, PhD, professor in the department of preventive medicine and community health at the Texas university and co-author of the meta-analysis, the ideal condom efficacy meta-analysis would require examining the original patient data from each study to calculate the disease-free time by risk group. She voices concern that newer groups of condom nonusers are confounded by HIV risk factors, especially intravenous drug use.
"It is extremely difficult now to get an average person who is having sex with an HIV-positive partner and who also just happens not to be using a condom," adds Weller. "I think that in order to get a better estimate of HIV transmission for condom nonusers, we need to go back to the really early studies, probably the hemophiliac studies, and recreate a historical cohort that represents an unbiased group."
However, the current meta-analysis offers good news for family planners, says Trussell. "My take-home message is that consistent use of condoms significantly reduces the risk of HIV transmission."
Why is it so important to increase condom use in heterosexual couples? Most of the new infections of HIV worldwide are due to heterosexual transmission.4 While male homosexual contact and intravenous drug use account for the majority of HIV infections in the United States, the numbers for transmission via heterosexual contact continue to climb.5
Women now comprise 19% of all adult AIDS patients in the United States, according to the Atlanta-based Centers for Disease Control and Prevention.6 The incidence rate has increased substantially among young women born between 1970 and 1974 who acquired AIDS through heterosexual contact. This increase suggests that successive cohorts of young women will be at risk for infection as they enter their teen and adult years. (The March 1998 issue of STD Quarterly, inserted in Contraceptive Technology Update, focused on the increasing AIDS rate among women; see p. 35 of that insert.)
In 1988, about 13% of sexually active couples in the United States were using condoms, and that number increased to almost 20% in 1995.7 While progress is being made in reaching U.S. public health goals for condom use, results from a 1999 study show that condom use continues to lag, especially among those at high risk for HIV.8 (See the May 1999 STD Quarterly, p. 3, for details.)
"Data shows that people around the world, particularly never-married men, are starting to change their behavior to avoid AIDS," says Upadhyay. "Still, many more people at risk do not protect themselves."
References
1. Davis KR, Weller SC. The effectiveness of condoms in reducing heterosexual transmission of HIV. Fam Plann Perspect 1999; 31:272-279.
2. Gardner R, Blackburn RD, Upadhyay UD. Closing the condom gap. Population Reports. Series H, No. 9. Baltimore: Johns Hopkins University School of Public Health, Population Information Program; April 1999.
3. Hatcher RA, Trussell J, Stewart F, et al. Contraceptive Technology. 17th ed. New York City: Ardent Media; 1998.
4. Daley CL, Càrceres CF, Choi K-H, et al. "International Epidemiology of HIV/AIDS." In: Cohen PT, Sande MA, Volberding PA, eds. AIDS Knowledge Base. 3rd ed. Philadel phia: Lippincott, Williams, & Wilkins; 1999.
5. Osmond D. "Epidemiology of HIV/AIDS in the United States." In: Cohen PT, Sande MA, Volberding PA, eds. AIDS Knowledge Base. 3rd ed. Philadelphia: Lippincott, Williams, & Wilkins; 1999.
6. Wortley PM, Fleming PL. AIDS in women in the United States. JAMA 1997; 278:911-916.
7. Bankole A, Darroch JE, Singh S. Determinants of trends in condom use in the United States, 1988-1995. Fam Plann Perspect 1999; 31:264-271.
8. Anderson JE, Wilson R, Doll L, et al. Condom use and HIV risk behaviors among U.S. adults: Data from a national survey. Fam Plann Perspect 1999; 31:24-28.
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