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The interconnectedness of HIV and other sexually transmitted diseases (STDs) grows increasingly apparent as biomedical and behavioral scientists learn more about people’s susceptibility and risks. CDC is applying new research to the prevention of all major STDs, including HIV infection, and is working to ensure communities have the information they need to design, implement, and evaluate comprehensive approaches to HIV and STD prevention.
Globally, an estimated 333 million new cases of curable STDs occur each year among adults, according to 1995 estimates by the World Health Organization. STDs in the United States have reached epidemic proportions with an estimated 12 million new cases each year. Of these, 3 million occur among teenagers, 13 to 19 years old. STDs are the most common reportable diseases in the United States.
The sexual spread of HIV in the United States has paralleled that of other STDs. For example, the geographic distribution of heterosexual HIV transmission closely parallels that of other STDs. Most of the health districts with the highest syphilis and gonorrhea rates in the United States are concentrated in the South, the same part of the nation with the highest HIV prevalence among childbearing women. Researchers have long recognized that the risk behaviors which place individuals at risk for other STDs also increase a person’s risk of becoming infected with HIV. STD surveillance can provide important indications of where HIV infection may spread, and where efforts to promote safer sexual behaviors should be targeted.
There is now strong evidence that other STDs increase the risk of HIV transmission and, conversely, that STD treatment reduces the spread of HIV.
With nearly 1 million Americans infected with HIV, most of them through sexual transmission, and an estimated 15 million cases of other sexually transmitted diseases (STDs) occurring each year in the United States, effective strategies for preventing these diseases are critical. Refraining from having sexual intercourse with an infected partner is the best way to prevent transmission of HIV and other STDs. But for those who have sexual intercourse, latex condoms are highly effective when used consistently and correctly.
The correct and consistent use of latex condoms during sexual intercourse- vaginal, anal, or oral-can greatly reduce a person’ s risk of acquiring or transmitting most STDs, including HIV infection, gonorrhea, chlamydia, trichomonas, human papilloma virus infection (HPV), and hepatitis B. Protecting yourself and others against STDs is important because many of these diseases have serious complications. Protecting yourself and others against HIV is important because it is life threatening and has no cure.
Laboratory studies show that latex condoms are effective barriers to HIV and other STDs. In addition, several studies provide compelling evidence that latex condoms are highly effective in protecting against HIV infection when used for every act of intercourse. This protection 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 2-year study of discordant couples in Europe, among 124 couples who reported consistent use of latex condoms, none of the uninfected partners became infected. In contrast, among the 121 couples who used condoms inconsistently, 12 (10%) of the uninfected partners became infected. In another study, among a group of 134 discordant couples who did not use condoms at all or did not use them consistently, 16 partners (12%) became infected. This contrasts markedly with infections occurring in only 3 partners (2%) of the 171 couples in this study who reported consistently using condoms over the 2-year period. Similarly, in a recent study among discordant couples in Haiti, 1 of 42 uninfected partners (2%) became infected with consistent condom use and 19 of 135 who used condoms inconsistently (14%) became infected.
Condoms are classified as medical devices and are regulated by the Food and Drug Administration (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 tested electronically for holes.
Several studies clearly show that condom breakage rates in this country are less than 2%. Most of the breakage and slippage likely is due to incorrect use 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. Studies also indicate that condoms slip off the penis in about 1-5% of acts of vaginal intercourse and slip down (but not off) about 3-13% of the time.
Some persons have expressed concern about studies that report higher 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. In fact, latex condoms are highly effective for pregnancy prevention, but only when they are used properly. Research indicates that only 30-60% 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 from start to finish. Incorrect use contributes to the possibility that the condom could leak at the base or break.
As mentioned previously, the primary reason that condoms sometimes fail to prevent HIV/STD infection or pregnancy is incorrect or inconsistent use, not failure of the condom itself. Consistent use means using a condom with each act of intercourse. Correct condom use includes all of the following steps:
If stored properly, condoms are good for 5 years after the manufacturing date. Condoms lubricated with spermicide may remain good for only 2 years. Condom users should make sure that the condom expiration date has not passed or the manufacturing date does not indicate the condom is too old.
There are several types of condoms. Nearly all types offer protection against HIV and other STDs.
Latex condoms for men. Latex condoms are made of a particular kind of rubber. Laboratory studies show that intact latex condoms provide a highly effective barrier to sperm and micro-organisms, including HIV and the much smaller hepatitis B virus. Their effectiveness has been proven over many years.
Synthetic condoms. For people who are allergic to latex, several new types of materials are being used to make condoms. One new type is polyurethane, a soft plastic. Another new type is Tactylon TM *, a synthetic latex. Lab tests have shown that both these materials provide an effective barrier against sperm, bacteria, and viruses such as HIV.
Polyurethane condoms for women. The female condom (Reality TM* ) fits inside the vagina and covers some of the area outside of the vagina. It also is made of polyurethane.
When a male condom cannot be used, couples should consider using a female condom. Unlike latex condoms, synthetic condoms such as male and female polyurethane condoms can be used with either water-based or oil-based lubricants.
Although not as thoroughly tested as latex condoms, synthetic condoms likely provide similar protection.
Lambskin condoms. These condoms are made from animal membranes that contain tiny holes. While they can prevent pregnancy, they should not be used for STD or HIV prevention because viruses may be able to pass through these holes.
Novelty condoms. Novelty (play) condoms are for sexual amusement only. The FDA does not allow them to be labeled as condoms, and they should never be used for STD/HIV or pregnancy prevention.
Spermicides. Although studies indicate that nonoxynol-9, a spermicide, kills HIV in laboratory testing, it is not clear whether spermicides used alone or with condoms during intercourse provide protection against HIV. Therefore, latex condoms with or without spermicides should be used to prevent sexual transmission of HIV.
Oral protection. Even though their risk is less than with unprotected anal and vaginal sex, people who engage in oral sex can reduce their risk of getting HIV or another STD by placing a barrier over the vagina or anus. In addition to the male condom, a product designed to reduce the risk of acquiring an STD during oral sex is now being sold in the United States. The Sheer Glyde Dam TM* is a 10" x 6" latex sheet that the FDA has authorized for marketing in the United States. Plastic food wrap, dental dams (pieces of latex used by dentists), and condoms that have been cut open all have been used to cover the vagina or anus during oral sex, although there is no information about how well these materials work.
Five U.S. studies of specific sex education programs have demonstrated that HIV education and sex education that included condom information either had no effect upon the initiation of intercourse or resulted in delayed onset of intercourse; five studies of specific programs found that HIV/sex education did not increase frequency of intercourse, and a program that included development of skills to negotiate safer sexual behavior actually resulted in a decrease in the number of youth who initiated sex. In addition, a World Health Organization (WHO) review cited 19 studies of sex education programs that found no evidence that sex education leads to earlier or increased sexual activity in young people. In fact, five of the studies cited by WHO showed that such programs can lead to a delay or decrease in sexual activity. In a recent study of youth in Los Angeles, an HIV prevention program focusing on condom use did not increase sexual activity or the number of sex partners. But condom use did increase among those who were already sexually active. A 1987 study of young U.S. men who were sent a pamphlet discussing STDs with an offer of free condoms also did not find any increase in the youths’ reported sexual activity.
In summary, STDs, including HIV infection, are preventable, and condoms represent an effective prevention tool. A recent analysis estimated that, for high-risk heterosexual men, the societal savings (in health care costs and productivity) per condom was $27, and for men who have sex with men, the savings per condom was more than $530 when condoms were used consistently and correctly with multiple partners.
The likelihood of transmission of HIV from an infected person to an uninfected person varies significantly depending on the type of exposure or contact involved. The risk of becoming infected with HIV through unprotected (without a condom) oral sex is lower than that of unprotected anal or vaginal sex. However, even a lower risk activity can become an important way people get infected if it is done often enough. One study sponsored by the Centers for Disease Control found that 7.8% (8 of 102) of recently infected men who have sex with men in San Francisco were probably infected through oral sex. Most of these men believed that the risk was minimal or non-existent.
Nearly half (3 of 8) of these cases reported oral problems, including occasional bleeding gums. Almost all (7 of 8) of these men reported to have had oral contact with pre-semen or semen.
Oral transmission of HIV is very difficult to single out as the only way that HIV is transmitted because few people engage exclusively in oral sex. A number of specific questions were asked by a trained evaluator. The participants’ risk behaviors were assessed by using clinical interviews, counselor intervention, epidemiologic interview, partner interview when possible, and final disposition of transmission risk. Of the 8 cases, 4 reported protected anal intercourse, without the condom breaking, with persons who were either HIV infected or had an unknown serostatus. Men in this study who reported that they were uncertain if the condom was used properly were eliminated from this study.
Yes and No. The percentage of recently infected men enrolled in this study who were probably infected through oral sex (8%) was higher than many researchers had thought likely or found in other studies. More media attention appeared to be placed on this particular study, probably because of the higher number of study participants. There appears to be evidence that higher risk activities (anal sex) among men who have sex with men is decreasing while lower risk activities (oral sex) among these men is increasing. Oral sex has always been considered a lower risk activity but is certainly not risk free.
The study results emphasize that any type of sexual activity with an infected person is a risk of HIV transmission. Oral sex with someone who is infected with HIV is certainly not risk free. Prevention of HIV is more important than ever. Some persons have indicated that they are less concerned about HIV because of new treatments and are being less careful. This study presents a wake-up call to everyone- that HIV is far from over and remains a serious, lifelong disease that is best to prevent. CDC’s recommendations on how to prevent sexual transmission of HIV remain the same. Protection requires abstaining from sexual activity or taking precautions with all types of intercourse- either having sex with only one uninfected partner, using condoms for sexual intercourse and oral sex, and using lower risk activities such as mutual masturbation.
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In the United States, HIV-related illness and death historically have had a tremendous impact on men who have sex with men (MSM). Even though the toll of the epidemic among injection drug users (IDUs) and heterosexuals has increased during the last decade, MSM continue to account for the largest number of people reported with AIDS each year. In 1999 alone, 15,464 AIDS cases were reported among MSM, compared with 10,138 among IDUs and 7,139 among men and women who acquired HIV heterosexually.
Overall, the number of MSM of all races and ethnicities who are living with AIDS has increased steadily, partly as a result of the 1993 expanded AIDS case definition and, more recently, improved survival. (See chart at right.)
Abundant evidence shows a need to sustain prevention efforts for each generation of young gay and bisexual men. We cannot assume that the positive attitudinal and behavioral change seen among older men also applies to younger men. Recent data on HIV prevalence and risk behaviors suggest that young gay and bisexual men continue to place themselves at considerable risk for infection with HIV and other sexually transmitted diseases (STDs).
These data highlight the need to design more effective prevention efforts for gay and bisexual men of color. The involvement of community and opinion leaders in prevention efforts will be critical for overcoming cultural barriers to prevention, including homophobia. For example, there remains a tremendous stigma to acknowledging gay and bisexual activity in African American and Hispanic communities.
Studies among MSM who are treated in STD clinics have shown consistently high rates of HIV infection, ranging from nearly 4% in Seattle to a high of almost 36% in Atlanta. Scientists know that the likelihood of both acquiring and spreading HIV is 2-5 times greater in people with STDs, and that aggressively treating STDs in a community can help to reduce the rate of new HIV infections. Along with prompt attention to and treatment of STDs, efforts to reduce the behaviors that spread STDs are critical.
Research has shown that high-risk behavior is continuing in some populations of MSM, including those who are infected with HIV. As the number of gay and bisexual men living with HIV increases, greater efforts must be made to reach them with behavioral interventions that can help them protect their own health and prevent transmission to others.
Female-to-female transmission of HIV appears to be a rare occurrence. However, case reports of female-to-female transmission of HIV and the well documented risk of female-to-male transmission of HIV indicate that vaginal secretions and menstrual blood are potentially infectious and that mucous membrane (e.g., oral, vaginal) exposure to these secretions have the potential to lead to HIV infection.
Through December 1998, 109,311 women were reported with AIDS. Of these, 2,220 were reported to have had sex with women; however, the vast majority had other risks (such as injection drug use, sex with high-risk men, or receipt of blood or blood products). Of the 347 (out of 2,220) women who were reported to have had sex only with women, 98% also had another risk–injection drug use in most cases.
Note: Information on whether a woman had sex with women is missing in half of the 109,311 case reports, possibly because the physician did not elicit the information or the woman did not volunteer it.
Women with AIDS whose only reported risk initially is sex with women are given high priority for follow-up investigation. As of December 1998, none of these investigations had confirmed female-to-female HIV transmission, either because other risks were subsequently identified or because, in a few cases, women declined to be interviewed. A separate study of more than 1 million female blood donors found no HIV-infected women whose only risk was sex with women. These findings suggest that female-to-female transmission of HIV is uncommon. However, they do not negate the possibility because it could be masked by other behaviors.
Surveys of risk behaviors have been conducted in groups of WSW. These surveys have generally been surveys of convenient samples of WSW that differ in sampling, location, and definition of WSW. As a result, their findings are not generalizable to all populations of WSW. These surveys suggest that some groups of WSW have relatively high rates of high-risk behaviors, such as injection drug use and unprotected vaginal sex with gay/bisexual men and injection drug users.
Although female-to-female transmission of HIV apparently is rare, female sexual contact should be considered a possible means of transmission among WSW. These women need to know:
Health professionals also need to remember:
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