You may have seen in the news over the last six months that they've found the DTaP to be less effective against pertussis (whooping cough) than its predecessor the DTP vaccine. Some vaccine deniers have picked up a study done in baboons and have made the erroneous claim that the vaccine can give a person pertussis (which if they had read the article more slowly they would have picked up that the baboons were purposefully exposed to pertussis to see what happened).
Here is an excellent post with citations that explains the study in more detail, what we learned from the study, and how it can help us formulate a better vaccine. (Plus, Red Wine and Applesauce is really just a great blog in general).
Making sense out of the baboon pertussis study
- Pertussis - The Baboon Study