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

The disease gonorrhea (GC) is a major public health problem in the United S tates, and the dynamics of the spread of GC through populations are complic ated and not well understood. Studies have drawn attention to the effect of concurrent sexual partnerships as an influential factor for determining di sease prevalence. However, little has been done to date to quantify the com bined effects of concurrency and within-partnership sex-act rates on the pr evalence of GC. This simulation study examines this issue with a simplified model of GC transmission in closed human populations that include concurre nt 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 mor e realistic in that the rate depends on the number of concurrent partners. After controlling for total number of sex acts, pseudo-equilibrium prevalen ce is higher with the fixed sex-act rate than under the concurrency-adjuste d rate in all the modeled partnership formation conditions.