The Tip Of The Iceberg: How Big Is The STD Epidemic In The U.S.?
December 2, 1998
What Are Sexually Transmitted Diseases (STDs)?
Sexually transmitted diseases or STDs represent a group of at least 25 infectious organisms that are transmitted through sexual contact. The eight most common include four
curable STDs-chlamydia, trichomoniasis, gonorrhea, and syphilis-and four viral,
incurable STDs-herpes simplex virus (HSV-2) or genital herpes, human papillomavirus (HPV), hepatitis B, and human immunodeficiency virus (HIV). There are also a number of syndromes caused by STDs, notably pelvic inflammatory disease (PID), which when left untreated is a leading cause of infertility among women.
Since 1980, eight new sexually transmitted pathogens have been recognized in the United States alone, in part because technological advances have enabled scientists to detect and identify new infectious organisms and their associated syndromes.
All STDs are preventable.
How Common Are STDs In The United States? Are STDs More Prevalent Now Compared To The Mid-1980s?
Sexually transmitted diseases are at epidemic proportions-half of the ten most frequently
reported infections to the Centers for Disease Control and Prevention (CDC) are STDs, including the most common, chlamydia. However, the scope of the epidemic and its impact is often underestimated by the public and unacknowledged by many health care professionals.
According to a panel of some of the nation's leading health experts convened by the American Social Health Association (ASHA) for the Kaiser Family Foundation in their report,
STDs in America: How Many Cases and At What Cost?, 15.3 million new cases of STDs occurred in the United States in 1996-3 million higher than the 12 million figure calculated by the CDC in the mid-1980s. The panel concludes that the higher estimate is "mainly because of improved detection techniques [that] have made it possible to identify asymptomatic ("silent") infections that were undercounted in the past." Furthermore, the panel notes that new estimate most likely reflects a slight overall decrease in the actual number of STDs when previous underestimation is taken into account. They note that the true number of new infections could be as low as 10 million or as high as 20 million. Nonetheless, STDs are widespread throughout society and represent a growing threat to the nation's health and well-being.
Why Is It So Hard To Pin Down The Number Of STD Infections That Occur Each Year In This Country?
Most STDs go undiagnosed because they do not cause noticeable symptoms. These "silent" infections are only detected when individuals are tested for STDs; however, screening programs are not widespread. Furthermore, not all people with STDs obtain medical care and many of the services provided by private physicians for STD diagnosis and treatment go unreported.
Current surveillance systems do not give accurate estimates of the incidence and prevalence of all STDs in this country. Only three STDs-gonorrhea, syphilis and chlamydia-are reported to state health departments and the CDC. There is no national reporting for the other five major STDs-genital herpes, HPV, hepatitis B, HIV and trichomoniasis. (Some states have an HIV surveillance program.) Consequently, the incidence and prevalence of most STDs must be estimated, and it is therefore difficult to assess trends. As awareness grows and more people seek STD care, and health professionals recognize the importance of reporting, better reporting occurs.
What Is Known About Trends In STDs?
Improved detection and reporting of asymptomatic infections that were undercounted in the past has driven up the most current estimated incidence of some infections, notably human papillomavirus, trichomoniasis, and herpes. At the same time, better detection has enabled faster treatment and prevented the further spread of some bacterial STDs, the result of which is a drop in their incidence. For example, the number of reported chlamydial cases increased steadily in recent years, primarily due to better screening rather than more infections. Overall, as more chlamydial infections have been detected and treated, the number of new cases has fallen, from an estimated 4 million new cases to about 3 million annually.
Other trends:
- Genital herpes has grown by 30% in the last two decades; more than one in five people over the age of 12-45 million Americans-are now infected with this incurable viral STD.
- The diagnosis of symptomatic genital warts has risen dramatically during the last two decades and its asymptomatic counterparts, HPV infections of the cervix and vagina, have emerged as the most common STD among young, sexually active people. While some 5.5 million new HPV infections occur each year, it is estimated that at least 20 million people have been infected with HPV.
- An estimated 5 million new cases of trichomoniasis occur each year. Trends in the incidence and prevalence of the vaginal infections trichomoniasis and bacterial vaginosis, however, are generally unavailable due to limited surveillance.
- New cases of gonorrhea have declined over the late two decades by about one-third-from 1 million to 650,000; however, rates remain disproportionately high among teenagers and minorities.
- Rates of syphilis in the U.S. are at the lowest levels in 20 years, at 70,000 cases annually, putting the elimination of this STD in striking distance.
- Despite the availability of a vaccine, 77,000 new sexually transmitted cases of hepatitis B (HBV) occur annually; 750,000 people are now infected with sexually transmitted HBV.
- The annual number of new HIV cases in the United States has been stable for several years, with about half of new cases-20,000 infections per year-acquired through sexual transmission, and the majority of new cases occurring among minorities. About 560,000 people are now infected with HIV as a result of sexually transmission.
Who Is Affected Most By STDs?
STDs affect people of all racial, ethnic, cultural, social, economic, religious and age groups. People in all states and communities and social strata are at risk for acquiring an STD. However, women, teenagers and the disadvantaged are disproportionately affected by STDs. Some infections, such as herpes and HPV, are so highly prevalent that it is estimated that nearly everyone is at risk or already infected by these diseases.
Women are biologically more susceptible than men to becoming infected if exposed to an STD, and STDs are more likely to remain undetected in women, resulting in delayed diagnosis and treatment. As a result, women are also more likely to develop serious sequelae; complications for women include infertility, tubal pregnancy and cervical cancer. During one act of intercourse, a woman's risk of contracting gonorrhea may be as high as 90%, while the risk to a man is about 20-30%; and, the risk of contracting HIV has been estimated to be eight times higher from man to woman as it is from woman to man.
Teenagers and young adults are hit hardest by STDs. They are at high risk for acquiring an STD because they are more likely to have unprotected sex with multiple partners. About one-quarter of new cases of STDs each year occur among teenagers; two-thirds of new cases occur among 15-24-year-olds. By age 24, at least one in three sexually active people are estimated to have had an STD. Teenage girls are especially vulnerable to contracting gonorrhea and chlamydia, which can more easily infect the immature cervix.
What Are The Health And Economic Consequences Of STDs?
STDs place an enormous health burden on Americans. The health consequences of STDs affecting million of women, infants and men range from mild illnesses to serious long-term consequences including: various cancers, reproductive health problems such as infertility, ectopic pregnancy and miscarriage, other chronic illnesses, and even death. Incurable viral STDs, such as HPV and herpes, result in lifelong infection and complications. Furthermore,
STD infections increase susceptibility to HIV-people with an active syphilis or genital herpes infection, or who have chlamydia, gonorrhea or trichomoniasis are three to five times more likely to contract HIV than other people.
The direct and indirect public and private costs of STDs are substantial, as well. A 1996 Institute of Medicine report conservatively estimated that the total 1994 costs associated with major STDs and their related syndromes-chlamydia, gonorrhea, PID, syphilis, chancroid, herpes, HPV, hepatitis B and cervical cancer-was about $10 billion, and $17 billion when sexually transmitted HIV/AIDS infections are included.
ASHA's new report,
STDs in America: How Many Cases and At What Cost?, conservatively estimates the direct medical costs-what it would cost to treat all estimated STDs in the United States-to be $8.4 billion alone. This estimates does not include the wide-ranging indirect costs of STDs, such as lost wages and productivity due to an STD-related illness, out-of-pocket costs, or costs related to transmission to infants.
HIV accounts for half of all direct medical costs of STDs, at $4.5 billion annually. HPV incurs the highest direct medical costs of all STDs other than HIV, at $1.6 billion annually. Curable STDs incur nearly $2 billion in direct costs annually, primarily due to pelvic inflammatory disease (a complication of untreated gonorrhea and chlamydia that can lead to ectopic pregnancy, infertility and chronic pain), followed by trichomoniasis ($375 million) and chlamydia ($375 million).
How Knowledgeable Are People About STDS?
A 1998 Kaiser Family Foundation/
Glamour magazine survey found that most men and women of reproductive age (18-44) seriously underestimate how common STDs are and most also do not know about some of the most common, and potentially damaging, STDs. Furthermore, very few believe themselves to be at personal risk of contracting an STD.
While at least one in three Americans will contract an STD in their lifetime, the majority of men (74%) and women (69%) think that the rate is one in ten Americans or fewer. And, only a small proportion of men (14%) and women (8%) believe that they are personally at risk of contracting an STD. A third of Americans (36%) are not aware that having an STD increases a person's risk of becoming infected with HIV.
When asked to name STDs they have heard of, very few men and women can name the two most common STDs-HPV and trichomoniasis. Only 8% of men and 13% of women name HPV and just 2% of men and 3% of women name trichomoniasis. Only 34% of women and 22% of men name chlamydia-the most common bacterial STD in women and the leading preventable cause of infertility in this country.
A forthcoming study by The Alan Guttmacher Institute of a group of sexually active adult women to determine their interest in a vaginal microbicide for STD prevention found that three in ten women were currently worried about getting HIV or another STD.
How Much Of A Threat Is The Human Papillomavirus To Women's Health?
More than 5 million new cases of HPV occur each year in this country. While there are more than 70 types of human papillomavirus,
only some of these strains are strongly associated with cervical and other genital cancers. Two strains of HPV, type 16 and type 18, are believed to be responsible for 90% of all cervical cancer cases, leading to nearly 5,000 deaths per year in the United States.
Cervical HPV is the most common STD among young women however, most cases do not cause noticeable symptoms. A recently published study in
The New England Journal of Medicine found that over a period of three years, four in 10 of 608 sexually active, young college women had contracted cases of HPV. The effect of this STD on individual and public health is significant considering the recognized relationship between certain strains of the genital HPV infection and cervical dysplasia and cervical cancer. Although there are numerous small studies of its prevalence in certain groups, little is known about the probability of acquiring the infections and associated risk factors.
Are Trichomoniasis And Bacterial Vaginosis New STDs?
Vaginal infections caused by
Trichomonas vaginalis are among the most common found in women seeking reproductive healthcare. An estimated five million new cases of trichomoniasis or "trich" occur each year. While symptoms of this curable sexually associated condition in women vary, the majority of infected men have no symptoms.
Bacterial vaginosis or BV, another long-standing sexually associated condition, is the most frequent cause of vaginitis in sexually active women of reproductive age. Some cases of BV are not sexually contracted. BV is often known as gardnerella because of the bacteria,
Gardnerella vaginalis, often associated with the infection. While also common and curable, there are no current estimates of BV.
Who Should Be Screened For Chlamydia And How Often?
Chlamydia, the common name for the STD caused by
Chlamydia trachomatis, is now the most prevalent
reported disease in this country. Trichomoniasis and HPV are more common STDs but are not "notifiable" diseases. Chlamydia is asymptomatic in as many as nine out of 10 infected women. Asymptomatic infections often result in a delay in treatment, leading to a greater probability of the transmission to sexual partners and the development of an upper genital tract infection. Genital chlamydial infection is the leading cause of preventable infertility and ectopic pregnancy.
The reported number of new chlamydia cases has risen in recent years, mainly because of more screening rather than more infections. Overall, as more infections have been diagnosed and treated, however, the incidence of this STD has fallen from an estimated 4 million to about 3 million each year.
Decision-making regarding who and when to screen for chlamydia infection has commanded a fair amount of attention in clinical circles in recent years. While universal screening of sexually active women has merit, given the devastating effects of this often-asymptomatic, untreated disease, universal screening is expensive. Selective screening approaches are therefore more often employed. However, the criteria by which such selective screening guidelines are determined varies.
The 1998 revised guidelines issued by the CDC recommend screening for chlamydial infection for all sexually active teens and young adults up to age 24, especially if they have had a new sex partner or more than one partner or if they are using barrier contraceptive inconsistently.
Two studies published in the July/August 1997 issue of
Family Planning Perspectives on selective screening criteria found that testing young women for chlamydia solely on age detects a high proportion of infections. One compared the detection of infection in women based on the CDC guidelines with detection using young age or behavioral risk as criteria. The authors concluded that age is the single most important screening criterion but testing should also consider risk profile and prevalence of the infection in specific communities. The second study evaluated the reliability of eight self-reported risk factors as a means to identify women with chlamydia. This study found that screening based only on reported risk factors does not detect a sufficiently high proportion of infections, and again, that age is the most important predictor.
A recently published three-year study of Baltimore teenagers (who were primarily African American and from low-income families) by Johns Hopkins University researchers found that roughly one-third of a group of 3,200 sexually active teenagers were infected with chlamydia. As a result of their findings, they recommend the screening of all sexually active teenagers for chlamydia infection every six months, rather than the recommended routine annual screening of sexual active young women under age 24 by the CDC.
Are There Any New Treatments For Herpes?
This incurable viral infection has grown by 30% in the last two decades in this country. Genital herpes now affects at least 45 million Americans-more than one in five Americans over the age of 12. One million new cases of herpes occur each year. Most herpes infections do not cause noticeable symptoms but can still be contagious. In fact, less than a quarter of infected Americans perceive themselves ever to have had genital herpes.
Recent studies underscore that just because a person with herpes does not have any noticeable symptoms does not mean he or she is not contagious. Herpes is most easily spread when people have sex during an outbreak (when sores or other symptoms are present) or during prodrome (the period just before an outbreak, often identified by genital itching or tingling). However, a recent study found that when couples with one herpes-infected partner used condoms or abstained during symptomatic periods, but had unprotected intercourse during aymptomatic periods, 17% of women and 4% of men became infected over the course of a year. The study revealed that those most likely to become infected:
- Are women, primarily because anatomical differences make women more susceptible to infection;
- Have a partner who became infected with herpes just within the past year;
- Have a partner who has frequent outbreaks, which increases his or her asymptomatic-but contagious-viral "shedding" between outbreaks; and
- Have never been infected with oral HSV-1, the virus that causes cold sores.
Some of the latest developments in herpes testing and treatment include: A study found that a three-day regimen (Valtrex) works as well as the FDA-approved five-day regimen for treating genital herpes outbreaks-and costs 40% less with no difference in outcome. Another study found that taking an antiviral drug (Famvir) daily reduce asymptomatic "shedding" among women from 3% of days to 0.4-0.5% of days, which is thought to help prevent transmission to their sexual partners. A new herpes blood test, called POCkit by Diagnology Ltd., is in clinical trials. It requires only a finger prick of blood and can produce tests results for HSV-2 in six minutes, without any lab work. The test has been on the market in Europe since late last year. Finally, several pharmaceutical companies are working on a vaccine for HSV-2.
Are There Any New Advances In The Treatment And Prevention Of STDs?
There are a number of new developments in the area of diagnosis, treatment and prevention of STDs in the United States. Several new strategies have proven effective at lowering rates of available STDs in this country. Federal, state, and local disease control programs have appeared to be successful in dramatically reducing STDs. Education and counseling programs are linked with behavioral changes in some communities. And, there are new diagnostic techniques aiding health care providers in detecting and treating many asymptomatic infections and new curative treatments, such as single-dose medications that cure bacterial infections.
Last month, the American Medical Women's Association and Digene Corporation announced their plans to launch an educational campaign in 1999 to promote awareness of cervical cancer and its primary cause, HPV. They noted that cervical cancer is the second most common malignancy found in women, after breast cancer.
Scientists are developing substances that can kill or block some of the organisms that cause STDs. These microbicidal substances presented in a cream, jelly, suppository or sponge, could potentially replace or augment the use of condoms, which currently offer the best protection against STDs, and spermicides, which offer some limited protection.
Scientists at St. Louis University School of Medicine began clinical trials in October 1998 for a vaccine developed by Merck Research Laboratories against one of the types of HPV believed to responsible for a high proportion of all cervical cancer cases.
In March 1997, 3M Pharmaceuticals announced that they received FDA approval to market the prescription cream, Aldara, for the treatment of external genital and perianal warts caused by HPV.
How Can The United States Better Fight The STD Epidemic?
Despite advances in diagnosis, treatment and prevention of STDs in this country, we continue to have one of the highest STDs rates in the industrialized world. An Institute of Medicine's 15-member expert Committee on Prevention and Control of Sexually Transmitted Diseases provided recommendations for public health program planning, policymaking and research addressing STD prevention and control in their 1996 report,
The Hidden Epidemic: Confronting Sexually Transmitted Diseases. The Committee concluded that an effective national system for STD protection and control does not currently exist in this country. Their overarching recommendation was for the nation to develop "an effective system of services and information that supports individuals, families, and communities, in preventing STDs including HIV, and ensures comprehensive, high-quality STD-related health services for all persons." The committee set forth a number of strategic goals:
- Develop strong leadership, strengthen investment, and improve information systems for STD prevention and control;
- Overcome barriers to adoption of healthy sexual behaviors by promoting knowledge and awareness, minimizing conflicting mass media messages, improving professionals' skills in sexual health issues, and supporting health behavior research;
- Design and implement essential STD-related services in innovative ways for adolescents and underserved populations by focusing on prevention, focusing on adolescents and establishing new venues for interventions; and,
- Ensure access to essential clinical services for STDs, by ensuring access to services in the community, improving the quality of dedicated public STD clinics, involving health plans and purchasers of health care, improving training and education of health care professionals, and improving clinical management of STDs.
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