In Social Networks
The standard mathematical definition of herd immunity applies only to "well-mixed populations," in which each infected individual is capable of transmitting the disease to any susceptible individual, regardless of social ties or location. More specifically, the relationship between the basic reproduction number R0 and the herd immunity threshold illustrated in the table above relies on a calculation that is valid only in well-mixed populations. Actual large populations, however, are better described as social networks, in which transmission can occur only between peers/neighbors. The shape of a social network can alter the level of vaccination required for herd immunity, as well as the likelihood that a population will achieve herd immunity. Compared to well-mixed populations, herd immunity in social networks is particularly fragile.
Read more about this topic: Herd Immunity
Famous quotes containing the words social and/or networks:
“It’s frightening how easy it is to commit murder in America. Just a drink too much. I can see myself doing it. In England, one feels all the social restraints holding one back. But here, anything can happen.”
—W.H. (Wystan Hugh)
“To be perfectly, brutally honest, those of us who are still carrying diaper everywhere we go are not at our most scintillating time of life....We need to remember that at one time in our lives, we all had senses of humor and knew things that were going on in the world. And if we just keep our social networks open, there will be people ready to listen when we once again have intelligent things to say.”
—Louise Lague (20th century)