Primary Syphilis: Serological Treatment Response to Doxycycline/Tetracycline versus Benzathine Penicillin

Case selection for analysis and treatment protocol for all first-time primary syphilis cases reported in Alberta, Canada, 1980-2001.

Serological treatment success according to treatment with benzathine penicillin G or doxycycline/tetracycline. Note: Serological treatment success was defined as a decrease in the baseline rapid plasma reagin test titer since treatment initiation by ≥4-fold by 6 months, or ≥8-fold decrease within 12 months, or ≥16-fold decrease within 24 months. If rapid plasma reagin test titer was 1:4, 1:2, or 1:1 at baseline, a serofast stable serology (ie, ±1 dilution from baseline) between 6 months and 12 months (184 days to 365 days) of treatment initiation also was considered treatment success. Treatment was considered to have failed if none of the above conditions were met, including if the rapid plasma reagin test titer increased from baseline by at least 4-fold between 1 month and 6 months (31 days to 183 days).