I've been aware of a frightful trend that is particularly manifested in controversial health issues: that science is not enough anymore.
When people fear a particular health risk, it seems irrelevant whether the best available science shows the risk to be negligible. They want more than scientific assurance--they want politicians. journalists, family and friends, to tell them there is absolutely no risk.
Every now and then an issue arises where many people keep on fearing a scientifically refuted health risk. This is the case of the alleged links between MMR vaccine and autism and the preservative thimerosal and autism.
British researcher, Tammy Boyce, has written a great book analyzing the communication of health risks: Health, Risk and News: The MMR Vaccine and the Media.
P.S. You can also check my blog on Vaccine Risk Communication.