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 is derived from the Latin "in + oculus" (eye). Though "innoculation/innoculate" (with a double "nn" rather than a single "n") is sometimes seen, this is incorrect, possibly erroneously thought to be related to innocuous, which is derived from the Latin "in + nocuus" (not harmful). Inoculation originated as a method for the prevention of smallpox by deliberate introduction of material from smallpox pustules into the skin. This generally produced a less severe infection than naturally-acquired smallpox, but still induced immunity to it. This first method for smallpox prevention, smallpox inoculation, is now also known as variolation. Inoculation has ancient origins