Day: June 5, 2009
Herd Immunity
Some infections can be eradicated from the face of the planet. Smallpox is the one example of disease eradication to date. Smallpox still exists in US and Russian labs, but there has been no wild cases since 1977. It is, like the Dorothy, history. Why were we able to eradicate smallpox? Three reasons: 1) There is only one form of smallpox. Unlike...