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Wednesday, May 10, 2006

Prevalence of Syphilis Seroreactivity in the United States: Data from the 2001-2002 National Health and Nutrition Examination Survey (NHANES)

Sami L. Gottlieb1, Victoria Pope1, Maya R. Sternberg1, John F. Beltrami1, Stuart M. Berman1, and Lauri Markowitz2. (1) Division of STD Prevention, CDC, 1600 Clifton Road, Mailstop E-02, Atlanta, GA, USA, (2) Division of STD Prevention, Centers for Disease Control and Prevention, 1600 Clifton Rd, MS E-02, Atlanta, GA, USA

Despite recent expansion of syphilis control efforts, there has not been a U.S. population-based measure of syphilis prevalence in 25 years.

To determine the prevalence of positive serologic tests for syphilis among a representative sample of the U.S. population.

Sera from 18-49 year-old participants in the 2001-2002 National Health and Nutrition Examination Survey (NHANES) were tested for syphilis IgG antibody using the syphilis-G enzyme immunoassay (EIA). Specimens with positive or indeterminate EIAs underwent rapid plasma reagin (RPR) testing. Specimens with RPR titers ≥1:8 were considered positive (more likely recent infection). Specimens with RPR titers <1:8 underwent confirmatory testing with Treponema pallidum particle agglutination (TP-PA); positive results were considered evidence of likely remote infection. Specimens with a negative EIA or TP-PA were considered negative for recent or remote syphilis.

Sera were available for 3028 participants. EIA testing was positive or indeterminate for 63, of which 5 (7.9%) had RPR titers ≥1:8. Of the remaining 58 specimens, 34 (58.6%) had positive TP-PA tests. Weighted prevalence of likely recent (RPR titer ≥1:8) syphilis infection was 0.06% and of likely remote (RPR titer <1:8) infection was 0.61%. Overall prevalence (recent or remote infection) was similar among males (0.67%) and females (0.68%) and increased with age (p=0.002), less education (p=0.02), and lower income (p=0.004). Non-Hispanic blacks had the highest prevalence (4.8%), followed by Mexican Americans (0.86%) and non-Hispanic whites (0%; p=0.002). Prevalence was 2.4% among those reporting non-heterosexual identity, versus 0.51% among heterosexuals (p=0.002).

Consistent with surveillance data, this nationally representative survey shows substantial disparities in syphilis by race/ethnicity and sexual orientation.

Further efforts are needed to reduce disparities in syphilis in the U.S.