Peterman, Thomas A. MD, MSc; Collins, Dayne E. BS; Aral, Sevgi O. PhD
IN OCTOBER 1999, SYPHILIS morbidity had reached historically low rates, and the Centers for Disease Control and Prevention (CDC), Division of STD Prevention (DSTDP) launched the national plan to eliminate syphilis in the United States. However, at that same time, Los Angeles, Chicago, Miami, and San Francisco began to see increases in rates of syphilis in men who have sex with men (MSM). In March 2000, Los Angeles declared there was an outbreak of syphilis in MSM. Outbreaks of syphilis among MSM were a threat to the syphilis elimination campaign.1 While control efforts had been focusing on disenfranchised heterosexuals in a decreasing number of areas, suddenly the risk had expanded to a new group of people in an increasing number of cities. The epidemics of syphilis and previously reported increases in gonorrhea among MSM also suggested a resurgence in human immunodeficiency virus (HIV) transmission might be occurring.2,3
The outbreak in Los Angeles and increases in other large cities stimulated a multifaceted response from the CDC. In October 2000, DSTDP facilitated a MSM syphilis consultation between health departments and community-based organizations providing services to gay communities. In 2001, the CDC released a public health bulletin on “Taking Action to Combat Increases in STD/HIV in MSM” and held 4 regional meetings to identify and address the issues fueling the problem. Efforts at the national level continued into 2002 with the creation of a cross-division (sexually transmitted disease [STD] and HIV) workgroup, an MMWR article focusing on the increases in primary and secondary (P&S) syphilis in the United States, and an action memo to state STD and HIV/acquired immunodeficiency syndrome (AIDS) program directors. By the end of 2002, several major cities were experiencing similar outbreaks. In January 2003, the CDC convened a meeting with representatives from the National Coalition of STD Directors and the National Association of State and Territorial AIDS Directors to ensure that the foundation for a collaborative local, state, and federal effort was in place. In January 2003, the CDC focused efforts on the 8 cities with the highest number of P&S syphilis cases in 2002 (Atlanta, Chicago, Ft. Lauderdale, Houston, Los Angeles, Miami, New York, and San Francisco). After completion of project area-specific profiles, on-site meetings, and the development of comprehensive intervention plans from each program, the CDC provided supplemental, one-time funds to the 8 cities to enhance interventions. While these efforts continue, many other cities/states have experienced increases in syphilis rates among MSM.
Responses in 8 Cities
This special edition of Sexually Transmitted Diseases documents some of the disease-control experiences of the 8 cities. The articles are a collaborative effort between representatives from all 8 programs, DSTDP, and other key persons involved in the effort to halt the epidemic. While journals normally publish science-based research findings or the outcome of rigorous evaluation, this special edition is designed to be useful for syphilis control programs and persons who staff these programs. The articles are meant to inform and educate readers about interventions that have been used and, in some cases, evaluated. They should spark dialogue, creative planning, and implementation of interventions. Programs differ, particularly in terms of available resources; however, the information in the articles may be adapted to enhance similar interventions in other programs or lead to implementation of new interventions. Just as individual programs are unique, so are the populations they serve. The gay community and subgroups in San Francisco are very different from those in Chicago. Understanding the differences enables a program to tailor an approach to the needs of their population. Evaluation data, when available, provide insight into potential success and appropriateness for other programs.
The current syphilis epidemic is different from past epidemics in ways that directly influence opportunities for intervention.3 Compared to syphilis patients in the past, gay men with syphilis are generally more affluent, older, and less likely to attend public STD clinics. Many are receiving care for their HIV infection. This epidemic began at a time when syphilis rates had reached an all-time low, so providers and persons at risk may be less aware of syphilis than in the past. Thus, prevention programs have worked to increase syphilis awareness among private providers by sending pictures of lesions and information on screening, treatment, and reporting; visiting key providers; and presenting at conferences and seminars.4 All 8 cities had social marketing campaigns to increase symptom recognition and encourage screening among persons at risk.5 Campaigns have included transit posters, palm cards, magazine advertisements, newspaper advertisements, television advertisements, websites, and even costumed characters.
Screening in nonmedical venues such as bathhouses and clubs was a key strategy in nearly all programs, but outreach testing has been expensive and has found relatively few infections.6 Screening is more cost-effective when it is done during routine medical visits of persons at risk. Partner notification can reach infected persons before they transmit infection to other partners and has advantages over screening when the prevalence is low. However, many MSM do not know their partners and do not value assistance with partner notification, so fewer infected partners are being notified than in the past.7 To find 1 infected partner, the programs must currently interview about 11 index cases compared to 4 or 5 in the past.7
Understanding the sexual networks of MSM at risk could facilitate interventions or possibly suggest new approaches.8 Bathhouses, sex clubs, and “circuit parties” have been named as venues where syphilis patients met partners, so health departments have worked with these organizations to reach their clients with testing and safe-sex information.9 The Internet has increasingly been cited as a place to meet sex partners. Some programs have learned to notify partners known only by an e-mail address, while others have done community outreach in Internet chat rooms.10 A more generalized wellness approach to health promotion was taken in New York City with a series of events, held at clubs offering services and screening for problems common to MSM, but these events are costly compared to adding similar services at regular sources of care.11
With so many different possible approaches, it is especially interesting to read the overall responses in San Francisco,12 Miami,13 and Ft. Lauderdale.13 Components that appear to be critical to intervention success have been community involvement, obtaining sufficient financial resources, recognition that some approaches will not work, and the ability to change responses accordingly.
While increases in syphilis morbidity among MSM in many areas of the United States have raised concern and stimulated a variety of programmatic responses, a theoretically meaningful description and interpretation of these epidemics is difficult to develop. Representative demographic and behavioral information on MSM is scarce. In the absence of such data, our understanding of the population transmission dynamics of syphilis (or any other sexually transmitted infection) in this population is highly limited, and so is our ability to predict how high incidence and prevalence rates may go or how long the apparent epidemics may continue. Similar limitations exist in our ability to evaluate programmatic efforts. Often we are unable to assess if the coverage of outreach interventions is adequate because we lack information on the size and distribution of the population at risk, the so-called target population.
In the past 2 decades, theoretical knowledge about the transmission dynamics of sexually transmitted infections has increased substantially.14–17 A key issue is understanding the variability and determinants of the trajectory of STI epidemics over time. Epidemic progression may include a trajectory where (a) the epidemic begins in a small core group and expands fairly rapidly yet stays within that core group; (b) the epidemic starts and expands in a core group then spreads to lower-risk populations; and (c) the epidemic rapidly involves a larger proportion of the low-risk population and spreads independently of core groups.14 Such epidemic trajectories are influenced by patterns of sexual behavior and sexual networks, as well as the biologic characteristics of the STI pathogen.
In the case of syphilis epidemics, some information on the characteristics of the pathogen is available. However, there are still unknowns related to, for example, the effects of coinfection with HIV or other STI on syphilis transmission or acquisition; the effects of antiretroviral therapies on syphilis transmission and acquisition; and the effects of other drug use on the same parameters. The inadequacy of information on the sexual networks and sexual behavior structure of populations of MSM is glaring. STD prevention programs lack knowledge of the size of populations of MSM in local areas. Moreover, it is clear that not all MSM are at risk for syphilis transmission; many are in mutually monogamous sexual partnerships. STD prevention programs also lack knowledge of the size of the MSM populations in their areas who are not at risk for acquisition or transmission. It is not clear if there are core groups of MSM in all local areas and, if so, what proportion of the total population of MSM belongs to the core group. We also have no information about patterns of movement into and out of core groups throughout the life course of MSM. Perhaps even more important is our lack of knowledge regarding the amount of sexual contact between core groups and the rest of the MSM population.
It is possible that most syphilis epidemics among MSM are core-group dependent epidemics and will decline and die out once a certain proportion of individuals in the core group are infected. However, in sexual systems marked by high volume of sexual contact between the core and periphery, this seems highly unlikely. Movement of MSM across local geographic areas further complicates the issue. Such movement increases numbers of susceptible MSM in a particular area, facilitates the introduction of the pathogen into new subpopulations, and establishes sexual bridges between infected and uninfected networks.18 Anecdotal information suggests that there is considerable movement of populations of MSM across the United States.19 The ability of MSM to identify sex partners over the Internet, inside and outside of their local area of residence,10 reduces the time it takes to form sexual links, further facilitating spread of infection.
The sexual behavior patterns and sexual networks of MSM are complex. The relative and absolute sizes of subpopulations are not known. Very little information exists on key parameters that influence epidemic trajectories of syphilis in these subpopulations. Thus, in the absence of syphilis control efforts, it is difficult to know how far syphilis would spread in these populations, how many individuals and what proportion of the population of MSM it would affect. Hence, it is difficult to know the impact of programmatic interventions discussed in this special issue, individually or in combination. While prevention programs can learn from the experience cited in this issue, we also hope that researchers will learn about the gaps in our knowledge base and develop studies to fill them.
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