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December 1963

Effect of Coincidental Penicillin Administration on the Spread of Syphilis: An Attempt at Quantitation

Author Affiliations


Germantown Hospital (Dr. Danehower); School of Medicine and Graduate School of Medicine, University of Pennsylvania (Dr. Schamberg).

Arch Dermatol. 1963;88(6):930-934. doi:10.1001/archderm.1963.01590240254043

For a variety of reasons, many early syphilitics go undiagnosed. They may:

  • remain untreated;

  • be treated on epidemiologic grounds as recent sex contacts of patients with infectious syphilis; or

  • be treated coincidentally (by "happenstance") with penicillin given for another disease.

Penicillin in ordinary dosage is effective against coexistent early syphilis. The broad spectrum antibiotics, in usual dosage, are not.

In this presentation an attempt has been made to show the effect of penicillin, administered for other diseases, on the spread of syphilis. That an expected 3.4% increase in new cases per "generation" of syphilis is converted to an 8.4% decrease by inclusion of the happenstance factor is demonstrated via diagrams. Its cumulation effect over several "generations" is readily apparent.

Happenstance penicillin treatment is considered to have been a major factor in the dramatic decline in the incidence of syphilis in the early fifties.

Less widespread use of penicillin for nonsyphilitic ailments is believed to be a major factor in the recent resurgence of syphilis.

The effectiveness of happenstance penicillin therapy in limiting the spread of syphilis lies primarily in:

  • Its ability to abbreviate the duration of infectiousness, often reaching (and curing) the early syphilitic before he has had any chance to disseminate his treponemes;

  • Its ability to reach (and cure) the unidentified syphilitic who escapes, and will continue to escape, the epidemiologic dragnet.

Because it is unlikely that penicillin will ever again be used as widely as it was ten to fifteen years ago, other methods must be sought to bring treponemicidal agents in curative dosage, early in his infectious period, to the unidentified syphilitic.