From Mindy Duggan's blog, as seen on The Vaccine Machine's facebook page about herd immunity:
Herd immunity was a term coined in the early 1930's by a researcher named A.W. Hendrich. The term was published in the American Journal of Epidemiology in 1933. Hedrich found that when 68% of children under the age of 15 had been infected with measles, therefore becoming immune, new cases of measles suddenly became sparse. Raging epidemics came to a halt. This was a huge breakthrough. The difference between herd immunity then and "herd immunity" now is that the term was originally intended to describe the natural immunity a population has after X percentage of the population is exposed to the natural disease, in its natural environment. This has absolutely nothing to do with vaccines. We have seen this type of herd immunity before, on every continent on earth. Herd immunity is a real, sure thing, but only with the NATURAL disease.
