Effect of concurrent partnerships and sex-act rate on gonorrhea prevalence

The disease gonorrhea (GC) is a major public health problem in the United States, and the dynamics of the spread of GC through populations are complicated and not well understood. Studies have drawn attention to the effect of concurrent sexual partnerships as an influential factor for determining disease prevalence. However, little has been done to date to quantify the combined effects of concurrency and within-partnership sex-act rates on the prevalence of GC. This simulation study examines this issue with a simplified model of GC transmission in closed human populations that include concurrent partnerships. Two models of within-partnership sex-act rate are compared; one is a fixed sex-act rate per partnership, and the other is perhaps more realistic in that the rate depends on the number of concurrent partners. After controlling for total number of sex acts, pseudo-equilibrium prevalence is higher with the fixed sex-act rate than under the concurrency-adjusted rate in all the modeled partnership formation conditions.