1. Successful prevention of syphilis infection with azithromycin in both HIV-negative and HIV-positive individuals, San Francisco, 1999-2003. J. D. Klausner, 1,2 K. Steiner, 1 R. Kohn 1 1 San Francisco Dept Public Health, San Francisco, CA 2 University of California, San Francisco, San Francisco, CA.

2. Background: Syphilis trends in San Francisco

3. Background: Current syphilis epidemic in San Francisco

4. Background: Previous studies on azithromycin and syphilis Hook EW, Stephens J, Ennis DM, Ann Intern Med, 1999 –randomized trial of 1 gram azithromycin vs. 2.4 mu benzathine penicillin for incubating disease –no reactive FTA-ABS at 3 months in either group Hook EW et al., Sex Trans Dis, 2001 –RCT of azithromycin vs. benzathine penicillin for syphilis cases –2 grams of azithromycin as effective as benzathine penicillin for treating disease

5. Background: Syphilis treatment in San Francisco Contacts: new cases versus “epi treatment” –2.4 mu benzathine penicillin G I.M. (“bicillin”) –100 mg doxycycline P.O. BID for 14 days –1 gram azithromycin P.O. Field-delivered therapy with Azithromycin began March, 1999

6. Objective Compare observed success in treating incubating syphilis using azithromycin to success with other treatments in order to justify continued use of azithromycin

7. Methods: San Francisco STD Registry STD clinic medical record data Reported morbidity and reactive STS Interview data and field activity Screening data

8. Methods: Sample Data from 1999 through 2003 Non-reactive RPR or VDRL with any syphilis treatment (n=3812) Follow-up titer between 30 and 90 days after initial titer (n=151)

9. Methods: Measurements Outcome: any reactive titer defines treatment failure Biological false positives excluded from analysis HIV status measured from multiple sources, including self-reported status

10. Results: All patients

11. Results: By HIV Status

12. Conclusions Failure rate for azithromycin was not significantly greater than rate for bicillin Since no resistance to bicillin has been documented, apparent treatment failures likely indicate re-exposure Success in treatment did not vary between HIV-negative and HIV-positive clients

13. Limitations No way to distinguish treatment failure from re-exposure Not all exposed will develop disease No randomization –penicillin allergies –field versus clinic Small number of follow-up titers Wide confidence limits for negative results

14. Limitations No power to assess temporal trends –Azithromycin epi-treatment failures: November 2002 April 2003 July 2003 –Bicillin epi-treatment failure: April 1999

15. Further research Another randomized trial of azithromycin vs. bicillin –HIV-positive clients only –San Francisco & Los Angeles –Five years later than 1999 study by Hook

16. Thank you...