Outbreak in the age of syphilis elimination: Houston's 2012 syphilis outbreak and response

Houston/Harris County exhibits the highest number of syphilis cases compared to any county in Texas and has been ranked in the top 10 nationwide for the past 9 years. In a recent syphilis outbreak, the Houston Department of Health and Human Services (HDHHS) examined surveillance data for trends of primary and secondary syphilis (P&S) cases by subpopulation. In 2012, the overall P&S syphilis rate was slightly higher than Houston's 2007 outbreak (11.24 per 100,000 persons in 2012 and 11.20 per 100,000 in 2007) with 83.2% of these cases occurring in males. This increase follows a four-year decline in P&S syphilis rates. The last time this rate was exceeded was in 1995 before implementation of the National Plan to Eliminate Syphilis. In comparison to 2011, there was an 84.8% case increase in 2012. The greatest increases in cases were among those 45 years or older, while there was a 15.9% decrease in cases among those 15-19 years of age. Deviating from the established trend in Houston, large increases in cases have been among the white and Hispanic populations (137.1% and 126.3% respectively). In regard to HIV co-morbidity, it was found that 39.0% (n=185) of all interviewed P&S syphilis cases were HIV positive in comparison to 31.2% in the previous year. Additionally, 58.1% (n=172) of all interviewed P&S syphilis cases among MSM were HIV positive, a 136% increase in co-morbid cases from the previous year. After assessment of these trends, the HDHHS initiated a multi-faceted outbreak response plan to strategically target prevention and control efforts.