Absolutely not. knowing that you don't know something is the only way to learn.
here's something i found just now:
During the past century, the prototypical disease, variola major, caused mortality of 3% and 30% in the vaccinated and unvaccinated, respectively. Routine smallpox vaccination was discontinued in the United States in 1972. Immunity from prior smallpox vaccination wanes with time and at this point, the entire United States' civilian population is likely susceptible. However, persons who have been vaccinated in the past may experience less severe disease.
Please don't call yourself dumb for not knowing something- here's what Socrates had to say about that:
"He thinks that he knows something which he does not know, whereas I am quite concious of my ignorance. At any rate it seems that I am wiser than he is to this small extent, that I do not think that I know what I do not know.