RT Journal Article SR Electronic T1 How infectious is syphilis? JF The British Journal of Venereal Diseases JO Br J Vener Dis FD BMJ Publishing Group Ltd SP 217 OP 219 DO 10.1136/sti.59.4.217 VO 59 IS 4 A1 Schober, P C A1 Gabriel, G A1 White, P A1 Felton, W F A1 Thin, R N YR 1983 UL http://sti.bmj.com/content/59/4/217.abstract AB In a study of the sexual contacts of patients with primary and secondary syphilis, 65 of 127 (51%) contacts at risk developed syphilis. There was no significant difference between figures for homosexuals (48/98, 49%) and for heterosexuals (17/29, 58%). Our findings are similar to those of the prepenicillin era, but the question, Why are so few contacts infected? remains unanswered.