Gonorrhea Increase in South-Central Washington State, July 2013- December 2014

BACKGROUND:  After several years of a statewide decrease in the gonorrhea (GC) rate in Washington State (WA), the rate climbed sharply starting in July 2013. Sixteen counties in WA, including a cluster of six rural counties located in South-Central WA — Adams, Benton, Franklin, Grant, Kittitas, and Yakima Counties—experienced an increase in GC cases by 50% or more in 2013. The number of cases continues to rise in this region. The purpose of these analyses was to identify differences in GC cases reported before and during the period of increase. 

METHODS:  Case demographic, diagnosis, and treatment information was collected from the WA disease surveillance system for all GC cases residing in WA from 2006-2014. Case location was determined by the county of residence. Only cases residing in the 6-county region of interest were included in the outbreak analyses.  Analyses were stratified by the outbreak period (July 1, 2013 – December 31, 2014) and the preceding 6.5 year pre-outbreak period (January 1, 2006-June 30, 2013). Statistical significance was calculated using chi-square tests and t-tests.

RESULTS: During the pre-outbreak period, 1,313 cases were reported in this region, and 1,018 cases were reported during the outbreak period. Fewer females were diagnosed during the outbreak period (52.8%) than in the pre-outbreak period (59.2%) (p=.002). Of males diagnosed with GC in this region, significantly fewer were identified as men who have sex with men (MSM) during the outbreak period than in the pre-outbreak period (13.3% versus 19.6%, p=.007).  More cases in the outbreak period lacked race and ethnicity information (16.2%) compared to cases reported in the pre-outbreak period (7.5%). The average age of the cases reported in the outbreak period was significantly older compared to the average age of cases reported during the pre-outbreak period (28.5 years old compared to 26.0 years old, p<.0001).

CONCLUSIONS:  The recent GC outbreak in South-Central WA is different than previous GC trends in the same area. There were minimal changes to the overall population makeup over the study period. Proportionally fewer females, and males who report MSM have been reported in the outbreak population. Similarly, the average age of cases has increased by nearly 3 years. Future interventions should focus on adjusting education and interventions to accommodate the shifting demographics of people diagnosed with GC in South-Central WA.