Just one more day: the gap as population level determinant and risk factor for STI spread.

摘要

Patterns of sexual contact among individuals determine the spread of sexually transmitted infections (STIs) in populations. Increasingly, over the past 2 decades, specific aspects of sexual contact patterns have been identified as foci of attention in attempts to explain STI spread. The distribution of sex partner numbers, including its determinants and consequences, has emerged as a major explanatory sexual contact pattern parameter. Empirical and theoretical studies have highlighted the importance of sexual mixing patterns, sexual networks, timing of sex partnerships, sequential order among sex partners, and the duration of time between sex partnerships in STI epidemiology. An important determinant of transmission for STIs is the length of time ("gap") between the end of an individual's partnership with 1 sex partner and the start of their next partnership. Gaps can be either positive, indicating a nonzero interval between 2 partnerships, or negative, indicating overlapping or concurrent partnerships. Concurrent partnerships are known to accelerate the spread of STI in populations; in addition, partners' concurrent partnerships are a risk factor for STIs in individuals. However, even serially monogamous partnerships can be effectively concurrent if the gap between them is shorter than the infectious period. Transmission occurs only if the infected individual has effective contact with a susceptible person during the infectious period, a finite period after acquisition.