Epidemiology of Sexually Transmitted Diseases in Clark County, Washington: Outbreak Response and Evaluation of Trends, Risk Factors, and Public Health Resources

BACKGROUND: It is estimated that more than half of Americans will contract an STD in their lifetime, and while some are treatable and can be prevented from recurrence in the future, others have long lasting, adverse effects. Further, the transmission of STDs varies from population to population, and, without proper information on these disparities, infections may go undiagnosed until after proliferation or complications have already occurred. Since 2014, Clark County has experienced a significant rise in STD diagnoses, including an ongoing gonorrhea outbreak and the state’s ’s highest rate of congenital syphilis in 2016. Many factors may contribute to these and other concerning statistics on STDs in the region, including the presence of high risk populations, limited provider education, or a lack of accessible STD prevention and treatment services. In order to better understand and respond to this growing issue, a more complete analysis of surveillance data was developed.

METHODS: Current and retrospective data was obtained from the Washington State Public Health Information Management System (PHIMS) and analyzed using SAS 9.4, ArcGIS, and Microsoft Excel. Investigators completed descriptive analyses on demographic, geographic, and social risk factors, as well as subpopulation analyses among gonorrhea outbreak cases and men who have sex with men (MSM). Provider profiles, outlining medical provision and access to care in the region, were also developed.

RESULTS: This analysis identified trends and transitions in 14 factors among Clark County STD cases, including the shifting gonorrhea burden to younger individuals and the growing prevalence of infection in women. Additionally, risk factors such as drug abuse, prior STD diagnosis, and internet use to meet partners were all reported at increasing rates over the study period. A secondary analysis among MSM STD cases identified a notable decrease in the burden of gonorrhea and syphilis on this subgroup, which may be indicative of improved efforts targeting the population, but also the need for increased attention to individuals in other sexual orientation cohorts, where diagnoses have increased.

CONCLUSIONS: Population based analyses on the burden of STDs within a community are vital to informing the design of effective public health interventions including outreach, provider education, and response. The results of this study have been used to guide such activities, determine resource allocation, and develop further areas of study, in order to gain a better understanding of and response to the persistent public health issues at hand.