BCG vaccine 400 per 100,000 in that higher risk context). The age of the person and the frequency with which BCG is given has always varied from country to country. BCG is prepared from a strain of the attenuated (virulence-reduced) live bovine tuberculosis bacillus, "Mycobacterium bovis", that has lost its ability to cause disease in humans. Because the living bacilli evolve to make the best use of available nutrients, they become less well-adapted to human blood and can no longer induce disease when introduced into a human host. Still, they are similar enough to their wild ancestors to provide some degree of
Inoculation theory Inoculation theory Inoculation theory was developed by social psychologist William J. McGuire in 1961 to explain how attitudes and beliefs change, and more importantly, how to keep existing attitudes and beliefs consistent in the face of attempts to change them. Inoculation theory functions as a strategy to protect attitudes from change–to confer resistance to counter-attitudinal influences, whether such influences take the form of direct attacks or sustained pressures. The theory posits that weak counterarguments–arguments that are easily refuted–generate resistance within the receiver, enabling them to maintain their beliefs in the face of a future, stronger, attack. Following exposure to weak