Syphilis vaccine

Patent Pending No vaccine for syphilis is available as of 2015. The outer membrane of T. pallidum has too few surface proteins for an antibody to be effective. Efforts to develop a safe and effective syphilis vaccine have been hindered by uncertainty about the relative importance of humoral and cellular mechanisms to protective immunity,[citation needed] and because T. pallidum outer membrane proteins have not been unambiguously identified.