If someone you know gets sick from taking a flu shot, you will be less likely to get one even if it is statistically safe. In fact, if you see a story on the news about someone dying from the flu shot, that one isolated case could me enough to keep you away from the vaccine forever. On the other hand, if you hear a news story about how eating sausage leads to anal cancer, you will be skeptical, because it has never happened to anyone you know, and sausage, after all, is delicious. The tendency to react more rapidly and to a greater degree when considering information you are familiar with is called the availability heuristic.

David McRaney