Similar irrational fears prompted the development of the "acellular" version of the pertussis (whooping cough) vaccine, which is less effective than the previously used version of the vaccine. Pertussis is a serious illness, and now that many people refuse to use the vaccine, and even the people who use it can only get a type of vaccine that is less effective than the first vaccine,[1] the whole population is needlessly at risk for pertussis outbreaks.
[1] http://pediatrics.aappublications.org/content/early/2013/05/...