Incident syphilis among women with multiple admissions to jail in New York City.

Although early syphilis morbidity in New York City (NYC) has declined to a record low, syphilis seroreactivity among women jailed in NYC is approximately 25%. By use of a retrospective cohort-type analysis of longitudinal serologic and treatment data collected at the time of each incarceration, the incidence of syphilis infection among 3579 susceptible women jailed multiple times in NYC between 23 March 1993 and 10 April 1997 was estimated. Syphilis incidence densities were estimated by use of continuous, time-homogeneous Markov models.