Lecture Notes

STIs are common in the United States, but identifying exactly how many cases there are is impossible, and even estimating the total number is difficult. How common are STIs? STIs represent four of five most frequently reported infectious diseases. The US has the highest STI rate among industrialized nations. More pragmatic approaches to sexuality issues, more comprehensive school and public sexuality education, and easier access to healthcare in other countries contribute to lower STI rates in Canada, Japan, Australia, and countries of the western and northern Europe. It is estimated that there are 19 million new STI cases occur each year in the US. By age 25, one in two persons will get an STI, and half of all people will be infected at some point in their lifetime. In discussing disease statistics, or epidemiology, it is important to be able to distinguish between incidence and prevalence. Incidence is the number of new cases while prevalence is the total number of cases. Incidence represents the occurrence of an STI. On the other hand, prevalence is the wide extent of an STI.