Joshua Lederberg | Jul 11, 1993 | 5 min read
In 1900, infectious disease was the leading cause of mortality in the United States, accounting for at least 37 percent of deaths. By 1950, this had been mitigated to 6.8 percent and, by 1989, to 2.8 percent, with corresponding improvements in life expectancy. These numbers, of course, must be taken with a grain of salt, given the eventual preemptive role of infection in chronic illness, and many disorders whose infectious etiology is still to be recognized. Further, the relative importance