Is 3 Really What We Need? Relative Effectiveness of Benzathine Penicillin G and Doxycycline Treatment Regimens for Late or Unknown Duration Syphilis in 6 US Jurisdictions, 2016–2021

We did not observe a difference in treatment effectiveness between 1 versus 3 doses of BPG, or between 3 doses of BPG and doxycycline, for late or unknown duration syphilis. Additional observational and clinical studies with more complete treatment and serologic response information are needed to confirm these findings and inform practice recommendations.