Herd immunity was coined in 1933 by A.W. Hedrich who observed measles outbreaks over the course of thirty years. What he discovered was that if 68% of the population had measles through the natural course of infection, the rest of the community (or herd) was protected. But you see, vaccines aren’t natural and they don’t provide life-time immunity, and even if they did 68% would be the number needed for herd immunity, not 95%. Your (and my) herd immunity was threatened the minute vaccines came on the scene.
— Megan Heimer, Living Whole