Clinical Prevention Guidance
The prevention and control of STDs are based on the following five major strategies:
- education and counseling of persons at risk on ways to avoid STDs through changes in sexual behaviors and use of recommended prevention services;
- identification of asymptomatically infected persons and of symptomatic persons unlikely to seek diagnostic and treatment services;
- effective diagnosis, treatment, and counseling of infected persons;
- evaluation, treatment, and counseling of sex partners of persons who are infected with an STD; and
- pre-exposure vaccination of persons at risk for vaccine-preventable STDs.
Primary prevention of STDs begins with changing the sexual behaviors that place persons at risk for infection. Health-care providers have a unique opportunity to provide education and counseling to their patients (5,6). As part of the clinical interview, health-care providers should routinely and regularly obtain sexual histories from their patients and address management of risk reduction as indicated in this report. Guidance in obtaining a sexual history is available in Contraceptive Technology, 19th edition (7) and in the curriculum provided by CDC's STD/HIV Prevention Training Centers. Effective interviewing and counseling skills, characterized by respect, compassion, and a nonjudgmental attitude toward all patients, are essential to obtaining a thorough sexual history and to delivering prevention messages effectively. Key techniques that can be effective in facilitating rapport with patients include the use of 1) open-ended questions (e.g., "Tell me about any new sex partners you've had since your last visit," and "What's your experience with using condoms been like?"); 2) understandable language ("Have you ever had a sore or scab on your penis?"); and 3) normalizing language ("Some of my patients have difficulty using a condom with every sex act. How is it for you?"). The "Five P's" approach to obtaining a sexual history is an example of an effective strategy for eliciting information concerning five key areas of interest (Box 1).
Efforts should be made to ensure that all patients are treated regardless of individual circumstances (e.g., ability to pay, citizenship or immigration status, language spoken, or specific sex practices). Patients seeking treatment or screening for a particular STD should be evaluated for all common STDs. All patients should be informed about all the STDs for which they are being tested and notified about tests for common STDs (e.g., genital herpes) that are available but not being performed.
USPSTF recommends high-intensity behavioral counseling for all sexually active adolescents and for adults at increased risk for STDs and HIV (5,6). All providers should routinely obtain a sexual history from their patients and encourage risk-reduction using various strategies; effective delivery of prevention messages requires that providers communicate general risk-reduction messages relevant to the client and that providers educate the client about specific actions that can reduce the risk for STD/HIV transmission (e.g., abstinence, condom use, limiting the number of sex partners, modifying sexual practices, and vaccination), each of which is discussed separately in this report (see Prevention Methods ). Prevention counseling is most effective if provided in a nonjudgmental and empathetic manner appropriate to the patient's culture, language, sex, sexual orientation, age, and developmental level.
- "Do you have sex with men, women, or both?"
- "In the past 2 months, how many partners have you had sex with?"
- "In the past 12 months, how many partners have you had sex with?"
- "Is it possible that any of your sex partners in the past 12 months had sex with someone else while they were still in a sexual relationship with you?"
2. Prevention of Pregnancy
- "What are you doing to prevent pregnancy?"
3. Protection from STDs
- "What do you do to protect yourself from STDs and HIV?"
- "To understand your risks for STDs, I need to understand the kind of sex you have had recently."
- "Have you had vaginal sex, meaning 'penis in vagina sex'?" If yes, "Do you use condoms: never, sometimes, or always?"
- "Have you had anal sex, meaning 'penis in rectum/anus sex'?" If yes, "Do you use condoms: never, sometimes, or always?"
- "Have you had oral sex, meaning 'mouth on penis/vagina'?"
For condom answers:
- If "never:" "Why don't you use condoms?"
- If "sometimes:" "In what situations (or with whom) do you not use condoms?"
5. Past history of STDs
- "Have you ever had an STD?"
- "Have any of your partners had an STD?"
Additional questions to identify HIV and viral hepatitis risk include:
- "Have you or any of your partners ever injected drugs?"
- "Have any of your partners exchanged money or drugs for sex?"
- "Is there anything else about your sexual practices that I need to know about?"
Interactive counseling approaches directed at a patient's personal risk, the situations in which risk occurs, and the use of personalized goal-setting strategies are effective in STD/HIV prevention (5,6). One such approach, known as client-centered STD/HIV prevention counseling, involves tailoring a discussion of risk reduction to the patient's individual situation. Client-centered counseling can increase the likelihood that the patient undertakes or enhances current risk-reduction practices, especially among persons seeking STD care. One such approach, known as Project RESPECT, demonstrated that a brief counseling intervention led to a reduced frequency of STD/HIV risk-related behaviors and resulted in lowered acquisition rates for curable STDs, including trichomoniasis, chlamydia, gonorrhea, and syphilis (8,9). Practice models based on Project RESPECT have been successfully implemented in clinic-based settings. Other approaches use motivational interviewing to move clients toward achievable risk reduction goals. CDC provides additional information on these and other effective behavioral interventions at http://effectiveinterventions.org.
Interactive counseling can be used effectively by all health-care providers, counselors, and other clinical staff trained in counseling approaches. Extensive training is not a prerequisite for effective risk reduction counseling; however, the quality of counseling is improved when providers receive training in prevention counseling methods and skill-building approaches, providers are periodically observed when providing counseling and given immediate feedback by persons with expertise in the counseling approach, counselors are periodically evaluated and patients asked to evaluate their level of satisfaction, and providers have access to expert assistance or referral for challenging situations. Training in client-centered counseling is available through the CDC STD/HIV Prevention Training Centers.
In addition to individual prevention counseling, videos and large group presentations can provide explicit information concerning STDs and instruction to reduce disease transmission (e.g., how to use condoms correctly). Group-based strategies have been effective in reducing the occurrence of additional STDs among persons at high risk, including those attending STD clinics (10).
Because the incidence of some STDs, notably syphilis, is higher in HIV-infected persons, the use of client-centered STD counseling for HIV-infected persons has been strongly encouraged by public health agencies and other health organizations. Consensus guidelines issued by CDC, the Health Resources and Services Administration, the HIV Medicine Association of the Infectious Diseases Society of America, and the National Institutes of Health emphasize that STD/HIV risk assessment, STD screening, and client-centered risk reduction counseling should be provided routinely to HIV-infected persons (11). Several specific methods have been designed for the HIV care setting (12-14), and additional information regarding these approaches is available at http://effectiveinterventions.org.
Abstinence and Reduction of Number of Sex Partners
A reliable way to avoid transmission of STDs is to abstain from oral, vaginal, and anal sex or to be in a long-term, mutually monogamous relationship with an uninfected partner. For persons who are being treated for an STD (or whose partners are undergoing treatment), counseling that encourages abstinence from sexual intercourse until completion of the entire course of medication is crucial. A more comprehensive discussion of abstinence and other sexual practices than can help persons reduce their risk for STDs is available in Contraceptive Technology, 19th Edition (7). For persons embarking on a mutually monogamous relationship, screening for common STDs before initiating sex might reduce the risk for future disease transmission.
Pre-exposure vaccination is one of the most effective methods for preventing transmission of some STDs. Two human papillomavirus (HPV) vaccines are available for females aged 9–26 years to prevent cervical precancer and cancer (15,16): the quadrivalent HPV vaccine (Gardasil) and the bivalent HPV vaccine (Cervarix). Gardasil also prevents genital warts. Routine vaccination of females aged 11 or 12 years is recommended with either vaccine, as is catch-up vaccination for females aged 13–26 years. Gardasil can be administered to males aged 9–26 years to prevent genital warts (17). Details regarding HPV vaccination are available at www.cdc.gov/hpv.
Hepatitis B vaccination is recommended for all unvaccinated, uninfected persons being evaluated for an STD (3,4). In addition, hepatitis A and B vaccines are recommended for men who have sex with men (MSM) and injection-drug users (IDUs) (2-4); each of these vaccines should also be administered to HIV-infected persons who have not yet been infected with one or both types of hepatitis virus. Details regarding hepatitis A and B vaccination are available at http://www.cdc.gov/hepatitis.
When used consistently and correctly, male latex condoms are highly effective in preventing the sexual transmission of HIV infection. In heterosexual serodiscordant relationships (i.e., those involving one infected and one uninfected partner) in which condoms were consistently used, HIV-negative partners were 80% less likely to become HIV-infected compared with persons in similar relationships in which condoms were not used (18).
Moreover, studies show condoms can reduce the risk for other STDs, including chlamydia, gonorrhea, and trichomoniasis; by limiting lower genital tract infections, condoms also might reduce the risk for women developing pelvic inflammatory disease (PID) (19,20). In addition, consistent and correct use of latex condoms also reduces the risk for genital herpes, syphilis, and chancroid when the infected area or site of potential exposure is covered, although data for this effect are more limited (21-24). Additional information is available at www.cdc.gov/condomeffectiveness/latex.htm.
Cohort studies have demonstrated that condoms protect against the acquisition of genital HPV infection. A prospective study among newly sexually active women who were attending college demonstrated that consistent and correct condom use was associated with a 70% reduction in risk for HPV transmission (25). Use of condoms also appears to reduce the risk for HPV-associated diseases (e.g., genital warts and cervical cancer) and mitigate the adverse consequences of infection with HPV. Condom use has been associated with higher rates of regression of cervical intraepithelial neoplasia (CIN) and clearance of HPV infection in women (26) and with regression of HPV-associated penile lesions in men (27).
Condoms are regulated as medical devices and are subject to random sampling and testing by the U.S. Food and Drug Administration (FDA). Each latex condom manufactured in the United States is tested electronically for holes before packaging. Rates of condom breakage during sexual intercourse and withdrawal are approximately two broken condoms per 100 condoms used in the United States. The failure of condoms to protect against STD transmission or unintended pregnancy usually results from inconsistent or incorrect use rather than condom breakage (28).
Male condoms made of materials other than latex are available in the United States. Two general categories of nonlatex condoms exist. The first type is made of polyurethane or other synthetic material and provides protection against STDs/HIV and pregnancy equal to that of latex condoms (29). These can be substituted for latex condoms by persons with latex allergy. Although they have had higher breakage and slippage rates when compared with latex condoms and are usually more costly, the pregnancy rates among women whose partners use these condoms are similar to those associated with use of latex condoms (30).
The second type is natural membrane condoms (frequently called "natural" condoms or, incorrectly, "lambskin" condoms). These condoms are usually made from lamb cecum and can have pores up to 1,500 nm in diameter. Although these pores do not allow the passage of sperm, they are more than 10 times the diameter of HIV and more than 25 times that of HBV (29). Moreover, laboratory studies demonstrate that viral STD transmission can occur with natural membrane condoms (29). Use of natural membrane condoms for prevention of STDs is not recommended.
Providers should advise their patients that condoms must be used consistently and correctly to be effective in preventing STDs; providing instructions about the correct use of condoms can be useful. Communicating the following recommendations can help ensure that patients use male condoms correctly:
- Use a new condom with each sex act (i.e., oral, vaginal, and anal).
- Carefully handle the condom to avoid damaging it with fingernails, teeth, or other sharp objects.
- Put the condom on after the penis is erect and before any genital, oral, or anal contact with the partner.
- Use only water-based lubricants (e.g., K-Y Jelly, Astroglide, AquaLube, and glycerin) with latex condoms. Oil-based lubricants (e.g., petroleum jelly, shortening, mineral oil, massage oils, body lotions, and cooking oil) can weaken latex and should not be used.
- Ensure adequate lubrication during vaginal and anal sex, which might require the use of exogenous water-based lubricants.
- To prevent the condom from slipping off, hold the condom firmly against the base of the penis during withdrawal, and withdraw while the penis is still erect.
Laboratory studies indicate that the female condom (Reality) is an effective mechanical barrier to viruses, including HIV, and to semen. The first female condom approved for use in the United States consisted of a lubricated polyurethane sheath with a ring on each end that is inserted into the vagina. A newer version made from nitrile is now available in the United States.
A limited number of clinical studies have evaluated the efficacy of female condoms in providing protection from STDs, including HIV (31,32). Although female condoms are costly compared with male condoms, sex partners should consider using a female condom when a male condom cannot be used properly. The female condom also has been used for STDs/HIV protection during receptive anal intercourse (33); although it might provide some protection in this setting, its efficacy remains unknown.
In observational studies, diaphragm use has been demonstrated to protect against cervical gonorrhea, chlamydia, and trichomoniasis (34). A recent trial examined the effect of use of a diaphragm plus polycarbophil (Replens) lubricant on HIV acquisition in women in Africa relative to male condom use alone. The study revealed that neither the diaphragm nor the lubricant gel provided additional protective effect when compared with the use of condoms alone (35). Likewise, no difference by study arm in the rate of acquisition of chlamydia or gonorrhea occurred; however, data from participants who reported following the protocol for the use of these products suggested that consistent use of the diaphragm plus gel might reduce acquisition of gonorrhea (36). Diaphragms should not be relied on as the sole source of protection against HIV infection. Diaphragm and nonoxynol-9 (N-9) spermicide use have been associated with an increased risk for bacterial urinary-tract infections in women (37).
Topical Microbicides and Spermicides
Studies examining nonspecific topical microbicides for the prevention of HIV and STD have demonstrated that these products are ineffective (38,39). Studies of spermicides containing N-9 have demonstrated that they should not be recommended for STDs/HIV prevention (40), and more recent randomized controlled trials have failed to show a protective effect against HIV acquisition for BufferGel (a vaginal buffering agent), Carraguard (a carrageenan derivative) (41), cellulose sulfate (an HIV entry inhibitor), (42) and SAVVY (1.0% C31G, a surfactant) (43,44).
Initial results from a study in which participants used 0.5% PRO2000 vaginal gel (a synthetic polyanion polymer that blocks cellular entry of HIV) on a daily basis appeared promising, reducing the rate of HIV acquisition by 30% relative to no gel (45). However, a recent randomized trial of approximately 9,000 women failed to show any protective effect (46).
Topical antiretroviral agents for the prevention of HIV appear more promising. Use of tenofovir gel during sexual intercourse significantly reduced the rate of HIV acquisition (i.e., by 39%) in a study of South African women (47). Additional studies are being undertaken to elucidate the optimal dosing regimens for this drug.
Other products remain under study, including VivaGel, a topical vaginal microbicide. A list of products under development is maintained by the Alliance for Microbicide Development at www.microbicide.org.
Condoms and N-9 Vaginal Spermicides
Condoms lubricated with spermicides are no more effective than other lubricated condoms in protecting against the transmission of HIV and other STDs (www.cdc.gov/condomeffectiveness/latex.htm). Furthermore, frequent use of spermicides containing N-9 has been associated with disruption of the genital epithelium, which might be associated with an increased risk for HIV transmission (40). Therefore, use of condoms lubricated with N-9 is not recommended for STD/HIV prevention; in addition, spermicide-coated condoms cost more, have a shorter shelf-life than other lubricated condoms, and have been associated with urinary-tract infection in young women (37).
Rectal Use of N-9 Spermicides
N-9 can damage the cells lining the rectum, which might provide a portal of entry for HIV and other sexually transmissible agents. Therefore, it should not used as a microbicide or lubricant during anal intercourse by MSM or by women.
Nonbarrier Contraception, Surgical Sterilization, and Hysterectomy
Contraceptive methods that are not mechanical barriers offer no protection against HIV or other STDs. Sexually active women who use hormonal contraception (i.e., oral contraceptives, Norplant, and Depo-Provera), have intrauterine devices (IUDs), have been surgically sterilized, or have had hysterectomies should be counseled regarding the use of condoms and the risk for STDs, including HIV infection, because these women might incorrectly perceive that they are not at risk for these diseases. Women who take oral contraceptives and are prescribed certain antibiotics should be counseled about potential interactions (7).
Although male circumcision should not be substituted for other HIV risk-reduction strategies, it has been shown to reduce the risk for HIV and some STDs in heterosexual men. Three randomized, controlled trials performed in regions of sub-Saharan Africa where generalized HIV epidemics involving predominantly heterosexual transmission were occurring demonstrated that male circumcision reduced the risk for HIV acquisition among men by 50%–60% (48-50). In these trials, circumcision was also protective against other STDs, including high-risk genital HPV infection and genital herpes (51-54). Despite these data, male circumcision has not been demonstrated to reduce the risk for HIV or other STDs among MSM (55). The World Health Organization (WHO) and the Joint United Nations Programme on HIV/AIDS (UNAIDS) have recommended that male circumcision be scaled up as an effective intervention for the prevention of heterosexually acquired HIV infection (56). These organizations also recommend that countries with hyperendemic and generalized HIV epidemics and low prevalence of male circumcision expand access to safe male circumcision services within the context of ensuring universal access to comprehensive HIV prevention, treatment, care, and support. Similar recommendations have not been made in the United States, although evidence regarding the role of male circumcision in the prevention of HIV/AIDS is under review (57).
Emergency Contraception (EC)
Women who might have been exposed to STDs during a recent act of unprotected intercourse also are at risk for pregnancy. Providers managing such women should offer counseling about the option of EC if pregnancy is not desired. In the United States, EC products are available over-the-counter to women aged ≥17 years and by prescription to younger women. If these EC pill products are not readily accessible, many commonly available brands of oral contraceptive pills can effectively provide EC, but women must be instructed to take an appropriate and specified number of tablets at one time. All oral EC regimens are efficacious when initiated as soon as possible after unprotected sex, but have some efficacy as long as 5 days later. EC is ineffective (but is also not harmful) if the woman is already pregnant (58). More information about EC is available in the 19th edition of Contraceptive Technology (7) or http://ec.princeton.edu/emergency-contraception.html.
Insertion of an IUD up to 7 days after unprotected sex can reduce pregnancy risk by more than 99% (7). However, this method is not advisable for a woman who may have untreated cervical gonorrhea or chlamydia, who is already pregnant, or who has other contraindications to IUD use.
Postexposure Prophylaxis (PEP) for HIV and STD
Guidelines for the use of PEP aimed at preventing HIV infection as a result of sexual exposure are available and are discussed in this report (see Sexual Assault and STDs). Genital hygiene methods (e.g., vaginal washing and douching) after sexual exposure are ineffective in protecting against HIV and STD and might increase the risk for bacterial vaginosis, some STDs, and HIV (59).
Pre-exposure Prophylaxis (PrEP) for HIV and STD
Antiretroviral therapy (ART) has the potential to impact transmission and acquisition of HIV. In HIV-infected persons, ART reduces viral load and presumably reduces infectiousness (60). In HIV-uninfected persons, ART might reduce susceptibility to infection, a concept supported both by animal studies and by a study of safety and acceptability involving West African women (61,62). A randomized, placebo-controlled trial involving South African women recently demonstrated that use of tenofovir gel associated with sexual intercourse significantly reduced the rate of HIV and herpes simplex virus type 2 (HSV-2) acquisition by 39% and 51%, respectively (47,63).
Several large randomized controlled trials of PrEP are either underway or planned. These involve the oral use of non-nucleoside reverse transcriptase inhibitors (tenofovir or tenofovir-emtricitabine) or vaginal use of 1% tenofovir gel.
Retesting to Detect Repeat Infections
Retesting several months after a diagnosis of chlamydia or gonorrhea can detect repeat infection and potentially can be used to enhance population-based prevention (64). Further details on retesting can be found in the specific sections on chlamydia and gonorrhea within this report.
Partner management refers to a continuum of activities designed to increase the number of infected persons brought to treatment and disrupt transmission networks. Part of this continuum is partner notification — the process by which providers or public health authorities learn about the sex- and needle-sharing partners of infected patients and help to arrange for partner evaluation and treatment. Clinical-care providers can obtain this information and help to arrange for evaluation and treatment of sex partners directly or by cooperating with state and local health departments. The types and comprehensiveness of existing partner services and the specific STDs for which they are offered vary by provider, public health agency, and geographic area. Ideally, persons referred to such services should also receive health counseling and should be referred for other health services as appropriate.
Data are limited regarding whether partner notification effectively decreases exposure to STDs and whether it reduces the incidence and prevalence of these infections in a community. Nevertheless, evaluations of partner notification interventions have documented the important contribution this approach can make to case-finding in clinical and community contexts (65). When partners are treated, index patients have reduced risk for reinfection. Therefore, providers should encourage persons with STDs to notify their sex partners and urge them to seek medical evaluation and treatment. Further, providers can ask patients to bring partners with them when returning for treatment. Time spent with index patients to counsel them on the importance of notifying partners is associated with improved notification outcomes (66).
When patients diagnosed with chlamydia or gonorrhea indicate that their partners are unlikely to seek evaluation and treatment, providers can offer patient-delivered partner therapy (PDPT), a form of expedited partner therapy (EPT) in which partners of infected persons are treated without previous medical evaluation or prevention counseling. Because EPT might be prohibited in some states and is the topic of ongoing legislation in others (67), providers should visit www.cdc.gov/std/ept to obtain updated information for their individual jurisdiction. Any medication or prescription provided for PDPT should be accompanied by treatment instructions, appropriate warnings about taking medications (if the partner is pregnant or has an allergy to the medication), general health counseling, and a statement advising that partners seek personal medical evaluation, particularly women with symptoms of STDs or PID.
The evidence supporting PDPT is based on three clinical trials that included heterosexual men and women with chlamydia or gonorrhea. The trials and meta-analyses revealed that the magnitude of reduction in reinfection of index case-patients compared with patient referral differed according to the STD and the sex of the index case-patient (68-71). However, across trials, reductions in chlamydia prevalence at follow-up were approximately 20%; reductions in gonorrhea at follow-up were approximately 50%. Rates of notification increased in some trials and were equivalent to patient referral without PDPT in others. Existing data suggest that PDPT also might have a role in partner management for trichomoniasis; however, no single partner management intervention has been shown to be more effective than any other in reducing reinfection rates (72,73). No data support the use of PDPT in the routine management of patients with syphilis. No studies have been published involving PDPT for gonorrhea or chlamydia among MSM.
Public health program involvement with partner notification services varies by locale and by STD. Some programs have considered partner notification in a broader context, developing interventions to address sexual and social networks in which persons are exposed to STDs. Prospective evaluations incorporating the assessment of venues, community structure, and social and sexual contacts in conjunction with partner notification efforts have improved case-finding and illustrated transmission networks (74,75). While such efforts are beyond the scope of individual clinicians, support of and collaboration with STD programs by clinicians are critical to the success of social network-based interventions.
Certain evidence supports the use of the internet to facilitate partner notification (76), especially among MSM and in cases where no other identifying information is available, and many health departments now conduct formal internet partner notification (IPN) (http://www.ncsddc.org/Internet_Guidelines). Clinical providers are unlikely to participate directly in IPN. However, when discussing partner notification approaches with patients, they should be aware of the value of the internet in this type of communication and should know where to refer patients who are interested in using the internet to notify partners about their diagnosis.
The accurate and timely reporting of STDs is integral to efforts to assess morbidity trends, allocate limited resources, and assist local health authorities in partner notification and treatment. STD/HIV and acquired immunodeficiency syndrome (AIDS) cases should be reported in accordance with state and local statutory requirements. Syphilis, gonorrhea, chlamydia, chancroid, HIV infection, and AIDS are reportable diseases in every state. Because the requirements for reporting other STDs differ by state, clinicians should be familiar with the reporting requirements applicable within their jurisdictions.
Reporting can be provider- or laboratory-based. Clinicians who are unsure of state and local reporting requirements should seek advice from state or local health departments or STD programs. STDs and HIV reports are kept strictly confidential. In most jurisdictions, such reports are protected by statute from subpoena. Before conducting a follow-up of a positive STD-test result, public health professionals should consult the patient’s health-care provider to verify the diagnosis and to determine the treatments being received.