Travel time to health facilities in areas of outbreak potential: maps for guiding local preparedness and response.

BACKGROUND: Repeated outbreaks of emerging pathogens underscore the need for preparedness plans to prevent, detect, and respond. As countries develop and improve National Action Plans for Health Security, addressing subnational variation in preparedness is increasingly important. One facet of preparedness and mitigating disease transmission is health facility accessibility, linking infected persons with health systems and vice versa. Where potential patients can access care, local facilities must ensure they can appropriately diagnose, treat, and contain disease spread to prevent secondary transmission; where patients cannot readily access facilities, alternate plans must be developed. Here, we use travel time to link facilities and populations at risk of viral hemorrhagic fevers (VHFs) and identify spatial variation in these respective preparedness demands. METHODS AND FINDINGS: We used geospatial resources of travel friction, pathogen environmental suitability, and health facilities to determine facility accessibility of any at-risk location within a country. We considered in-country and cross-border movements of exposed populations and highlighted vulnerable populations where current facilities are inaccessible and new infrastructure would reduce travel times. We developed profiles for 43 African countries. Resulting maps demonstrate gaps in health facility accessibility and highlight facilities closest to areas at risk for VHF spillover. For instance, in the Central African Republic, we identified travel times of over 24 h to access a health facility. Some countries had more uniformly short travel times, such as Nigeria, although regional disparities exist. For some populations, including many in Botswana, access to areas at risk for VHF nationally was low but proximity to suitable spillover areas in bordering countries was high. Additional analyses provide insights for considering future resource allocation. We provide a contemporary use case for these analyses for the ongoing Ebola outbreak. CONCLUSIONS: These maps demonstrate the use of geospatial analytics for subnational preparedness, identifying facilities close to at-risk populations for prioritizing readiness to detect, treat, and respond to cases and highlighting where gaps in health facility accessibility exist. We identified cross-border threats for VHF exposure and demonstrate an opportunity to improve preparedness activities through the use of precision public health methods and data-driven insights for resource allocation as part of a country's preparedness plans.

Risk-based versus alternative algorithms for antibiotic prophylaxis among women seeking early suction abortion: a cost-effectiveness simulation.

BACKGROUND: Particularly in resource-poor settings, simple, inexpensive, and cost-effective algorithms are needed to direct antibiotic prophylaxis to prevent sequelae of infections with Chlamydia trachomatis, Neisseria gonorrhoeae, and bacterial vaginosis-associated organisms among women undergoing abortion. GOAL: To assess the prevalence of and risk factors for infections among women seeking abortion in Bali, Indonesia, and to use these data in designing a cost-effective risk-based prophylaxis algorithm. STUDY DESIGN: A cross-sectional analysis and data-based simulation of risk-based and alternative prophylaxis algorithms were performed. RESULTS: The risk-based algorithm would have provided prophylaxis to 70% (95% CI, 53-83%) of women with cervical infection, 64% (95% CI, 54-74%) of those with bacterial vaginosis, and 57% (95% CI, 42-72%) of those with trichomoniasis. For cervical infection, the algorithm was more cost effective than all others evaluated. The cost-effectiveness was acceptable for bacterial vaginosis. CONCLUSIONS: Risk-based algorithms may be cost effective in identifying women likely to benefit from preabortion prophylaxis. Prospective evaluation is needed to validate these findings.

The effect of treating sexually transmitted diseases on the transmission of HIV in dually infected persons: a clinic-based estimate. Ad Hoc STD/HIV Transmission Group.

BACKGROUND: The effect of sexually transmitted disease (STD) treatment on HIV transmission is a topic of considerable current interest and controversy. GOAL: To assess the potential effect of STD treatment on HIV transmission in persons who are dually infected with STD and HIV. STUDY DESIGN: Using data from eight STD clinic sites in the United States, the authors estimate the actual achievable reduction in HIV transmission by multiplying the prevented fraction associated with treatment of STDs (set at an average of 0.8) by the maximum potential reduction in HIV transmission achieved by treating STDs (using an average relative risk of 3.0 for increased HIV transmission in the presence of STDs). Subgroup analysis assessed infection proportions for genital ulcer disease, nonulcerative STDs, and any STD by sex, ethnicity, age, and sexual orientation. RESULTS: The maximum achievable reduction in HIV transmission from dually infected persons to their partners is approximately 33%. The actual achievable reduction is approximately 27% (range, 10.0-38.1%) at the eight clinic sites. If each of the 4,516 dually infected persons in this cohort experienced a single sexual exposure with an uninfected person, 28 HIV infections would occur in the absence of STD treatment whereas 16 infections would occur with STD treatment. CONCLUSIONS: The estimate of a 27% reduction provides a qualitative assessment of the potential impact of STD treatment on HIV transmission in the absence of any other behavioral intervention. Identification of dually infected persons in STD clinics is an important mechanism for targeting interventions to a social milieu with high risk for HIV infection and other STDs.

From epidemiological synergy to public health policy and practice: the contribution of other sexually transmitted diseases to sexual transmission of HIV infection.

OBJECTIVES: To review the scientific data on the role of sexually transmitted diseases (STDs) in sexual transmission of HIV infection and discuss the implications of these findings for HIV and STD prevention policy and practice. METHODS: Articles were selected from a review of Medline, accessed with the OVID search engine. The search covered articles from January 1987 to September 1998 and yielded 2101 articles. Methods used to uncover articles which might have been missed included searching for related articles by author, and combing literature reviews. In addition, all abstracts under the category "sexually transmitted diseases" from the XI and XII International Conferences on AIDS (Vancouver 1996 and Geneva 1998) and other relevant scientific meetings were reviewed. Efforts were made to locate journal articles which resulted from the research reported in the identified abstracts. All original journal articles and abstracts which met one of the following criteria were included: (1) studies of the biological plausibility or mechanism of facilitation of HIV infectiousness or susceptibility by STDs, (2) prospective cohort studies (longitudinal or nested case-control) which estimate the risk of HIV infection associated with specific STDs or STD syndromes, or (3) intervention studies which quantitate the effect which STD treatment can have on HIV incidence. RESULTS: Strong evidence indicates that both ulcerative and non-ulcerative STDs promote HIV transmission by augmenting HIV infectiousness and HIV susceptibility via a variety of biological mechanisms. These effects are reflected in the risk estimates found in numerous prospective studies from four continents which range from 2.0 to 23.5, with most clustering between 2 and 5. The relative importance of ulcerative and non-ulcerative STDs appears to be complex. Owing to the greater frequency of non-ulcerative STDs in many populations, these infections may be responsible for more HIV transmission than genital ulcers. However, the limited reciprocal impact of HIV infection on non-ulcerative STDs and the evidence that non-ulcerative STDs may increase risk primarily for the receptive partner (rather than bidirectionally) may modulate the impact of these diseases. The results of two community level randomised, controlled intervention trials conducted in Africa suggest that timely provision of STD services can substantially reduce HIV incidence, but raise additional questions about the optimal way to target and implement these services to achieve the greatest effect on HIV transmission. CONCLUSIONS: Available data leave little doubt that other STDs facilitate HIV transmission through direct, biological mechanisms and that early STD treatment should be part of a high quality, comprehensive HIV prevention strategy. Policy makers, HIV prevention programme managers, and providers should focus initial implementation efforts on three key areas: (i) improving access to and quality of STD clinical services; (ii) promoting early and effective STD related healthcare behaviours; and (iii) establishing surveillance systems to monitor STD and HIV trends and their interrelations.

Accelerated Campaign to Enhance STD Services (ACCESS) for youth: successes, challenges, and lessons learned.

BACKGROUND AND OBJECTIVES: Adolescents have the highest sexually transmitted disease (STD) incidence and are often hard to reach with preventive services. Fourteen youth-focused projects were funded by the Centers for Disease Control and Prevention in 1994 through 1995 to pilot innovative, locally relevant, locally acceptable approaches; expand the range and accessibility of services beyond clinic-based facilities; and stimulate increased commitment of local resources. DESIGN: Review and synthesis of 14 youth-focused, innovative projects. RESULTS: Most projects undertook multiple interventions (11/14) in multiple venues (9/14). The majority (9/14) incorporated behavioral interventions, and half offered clinical services in nontraditional settings such as detention facilities, schools, parks, and parking lots. Six projects used peer volunteers; four worked with community coalitions. Most (12/14) obtained local resources. Where assessed, parental support was strong for providing STD prevention services. CONCLUSIONS: These projects increased the access and range of services available to a substantial number of high-risk youth with high STD rates. However, sustaining and scaling-up pilot project activities will be resource intensive. Increased financial and training support to augment evaluation capacity will be critical for innovation to become an integral part of STD prevention programs.

Prevention agenda for genital herpes.

Few meeting participants envisioned a prevention and control program on the scale or scope of CDC's programs to prevent HIV infection, syphilis, gonorrhea, and chlamydial infection, but all agreed that the virtual absence of public health interventions to prevent genital herpes is no longer appropriate in light of evolving epidemiologic knowledge and other research advances. The ultimate scope of a national genital herpes prevention effort will depend in part on the results of the recommended research agenda, which probably will evolve over the better part of a decade. Numerous other STD prevention partners will also need to contribute to this effort and help to determine the makeup of future programs. Substantial new fiscal resources will be required both to implement the proposed research agenda and, depending on the results, to undertake the prevention efforts indicated by those studies. Competing STD prevention priorities and other national health needs will influence the availability of those resources. The consultants' meeting and the research and program activities summarized above are described in more detail in the full meeting report, which is posted on the Division's web site (www.cdc.gov/nchstp/dstd/dstdp.html) or may be requested directly from the Division. DSTDP is interested in receiving comments and suggestions about herpes prevention.

Social and behavioral correlates of pelvic inflammatory disease.

OBJECTIVES: To review the social and behavioral correlates of pelvic inflammatory disease (PID) in the light of the renewed interest in the transmission dynamics of communicable diseases, the new emphasis on health care seeking and health service provision, and increased attention to contextual and population level factors affecting morbidity. METHODS: Social and behavioral correlates of PID are reviewed using a conceptual scheme that matrixes the differences among risk factors for exposure, acquisition, and development of sequelae with the differences between individual-level risk factors and population-level determinants. RESULTS: Two major factors contribute to the development of PID: recurrent (or persistent) chlamydial infection of the cervix, which are geographically concentrated and associated with contextual variables, and critical delays in detection and treatment of cervical infection, which are amenable to interventions. CONCLUSIONS: Widespread screening for cervical infection followed by timely and appropriate treatment is key for prevention of PID. Health care seeking, provider training, and availability of detection technologies and drugs need to be improved.

The changing paradigm of sexually transmitted disease control in the era of managed health care.

Several trends in sexually transmitted diseases (STDs) have laid the foundation for a new paradigm for STD treatment and prevention that encompasses a community-wide, population-oriented approach. Public health STD programs, in partnership with a wide variety of community collaborators, will need to carry out the essential functions of public health-assessment, policy development, and assurance-by developing resources for community organizing and planning, enhanced information systems, and comprehensive training programs for professional staff and community partners. Community providers (particularly practicing clinicians and community and hospital clinics) will need to deliver primary prevention (community health promotion and clinical preventive services) and secondary prevention (screening and treatment) services while categorical STD clinics focus on providing care for high-risk, high-frequency STD transmitters who serve as the reservoir for much of a community's bacterial STDs. Managed care organizations and public health STD programs will need to formalize collaborative arrangements and capitalize on the strengths of each organization in order to have a population-level impact on STD transmission.

The dynamic topology of sexually transmitted disease epidemics: implications for prevention strategies.

Each sexually transmitted disease (STD) epidemic evolves through predictable phases, shaped by a dynamic interplay among the pathogen, the behaviors of the subpopulations in which it emerges, and the prevention efforts that are developed to limit its impact. As STD epidemics move through these phases, the sexual and social networks that fuel them become located in subpopulations characterized by progressively higher rates of sex partner change and less contact with the health care system. As a result, phase-appropriate prevention strategies and research issues are essential to reducing STDs and their consequences.

Effect of changes in human ecology and behavior on patterns of sexually transmitted diseases, including human immunodeficiency virus infection.

The last 20 years have witnessed six striking changes in patterns of sexually transmitted diseases (STDs): emergence of new STD organisms and etiologies, reemergence of old STDs, shifts in the populations in which STDs are concentrated, shifts in the etiological spectra of STD syndromes, alterations in the incidence of STD complications, and increases in antimicrobial resistance. For example, human immunodeficiency virus (HIV) emerged to devastate the United States with a fatal pandemic involving at least 1 million people. The incidence of syphilis rose progressively after 1956 to reach a 40-year peak by 1990. In both cases, disease patterns shifted from homosexual men to include minority heterosexuals. Over the last decade, gonorrhea became increasingly concentrated among adolescents, and several new types of antimicrobial resistance appeared. Three interrelated types of environments affect STD patterns. The microbiologic, hormonal, and immunologic microenvironments most directly influence susceptibility, infectiousness, and development of sequelae. These microenvironments are shaped, in part, by the personal environments created by an individual's sexual, substance-use, and health-related behaviors. The personal environments are also important determinants of acquisition of infection and development of sequelae but, in addition, they mediate risk of exposure to infection. These are, therefore, the environments that most directly affect changing disease patterns. Finally, individuals' personal environments are, in turn, molded by powerful macroenvironmental forces, including socioeconomic, demographic, geographic, political, epidemiologic, and technological factors. Over the past 20 years, the profound changes that have occurred in many aspects of the personal environment and the macroenvironment have been reflected in new STD patterns.

Delayed care of pelvic inflammatory disease as a risk factor for impaired fertility.

OBJECTIVE: We evaluated the relationship between delayed care of symptomatic pelvic inflammatory disease and impaired fertility. STUDY DESIGN: We used data from a cohort of women with clinically recognized pelvic inflammatory disease. Case patients were women with either ectopic pregnancy or infertility (n = 76); controls were women with intrauterine pregnancies (n = 367). RESULTS: Women who delayed seeking care for pelvic inflammatory disease were three times more likely to experience infertility or ectopic pregnancy than women who sought care promptly after adjustment for age, organism, year of diagnosis, and history of recent gynecologic events (95% confidence interval = 1.27, 6.11). This association was strongest for women with chlamydia; 17.8% (18/101) of those who delayed seeking care had impaired fertility, whereas 0.0% (0/13) of those who sought care promptly suffered known sequelae. CONCLUSIONS: Women with pelvic inflammatory disease who delay seeking care are at increased risk for infertility and ectopic pregnancy. Furthermore, our data suggest that prompt evaluation and treatment of chlamydial pelvic inflammatory disease can prevent these sequelae.

Disease prevalence among women attending a sexually transmitted disease clinic varies with reason for visit.

Prevalence of sexually transmitted diseases (STD) and selected behavioral and demographic variables were evaluated in 279 women attending a Baltimore STD clinic, using a standardized questionnaire and cultures for Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis. Stratified by reason for clinic visit, 102 (37%) of 279 women attending the clinic stated that they were recent contacts to men with STDs with the majority (59 out of 102, or 58%) reporting gonorrhea contact as their reason for visit. Another 124 women (44%) came to the clinic for symptom evaluation, and 53 (19%) for other reasons. Prevalence of STDs was higher among those attending as contacts than among noncontacts: 35% versus 15% for N. gonorrhoeae; 26% versus 16% for C. trachomatis; and 27% versus 15% for T. vaginalis (P less than 0.05 for each). Furthermore, multiple infections were found in 23% of those attending as contacts but only in 10% of noncontacts (P less than 0.001). In general, patients reporting contact with an infected person were also less likely to report symptoms (43% versus 34%, P less than 0.001), despite increased disease prevalence. These data suggest that multiple STDs are often present in women attending STD clinics, irrespective of reason for visit. Merely treating women for reported exposure without further evaluation will fail to identify a substantial number of women coinfected with other organisms.

Epidemiological synergy. Interrelationships between human immunodeficiency virus infection and other sexually transmitted diseases.

Understanding the role of other sexually transmitted diseases (STDs) in the transmission of human immunodeficiency virus (HIV), the role of STDs in progression of HIV disease, and the role of HIV infection in alterations of natural history, diagnosis, or response to therapy of STDs is critical to the development of optimal strategies for HIV control. One hundred sixty-three studies on the interrelationships between HIV infection and other STDs were examined. Of 75 studies on the role of STDs in HIV transmission, the 15 analyses of examination or laboratory evidence of STDs adjusted for sexual behavior showed that both ulcerative and nonulcerative STDs increase the risk of HIV transmission approximately 3- to 5-fold. Due to limited data, the role of STDs in progression of disease remains unclear. Preliminary data from 83 reports on the impact of HIV infection on STDs suggest that, at a community level, HIV infection may increase the prevalence of some STDs (e.g., genital ulcers). If coinfection with HIV prolongs or augments the infectiousness of individuals with STDs, and if the same STDs facilitate transmission of HIV, these infections may greatly amplify one another. This "epidemiological synergy" may be responsible for the explosive growth of the HIV pandemic in some populations. Effective STD control programs will be essential to HIV prevention in these communities.