Giving prominence to potentially unfounded concerns, or overstating concerns in relation to the risk of not vaccinating is also an issue.
"Before the introduction of pertussis immunisation in the 1950s, the average annual number of notifications in England and Wales exceeded 100,000. In 1972, when vaccine acceptance was over 80%, there were only 2069 notifications of pertussis. Public anxiety about the safety and efficacy of the vaccine, following a report published which suggested a possible link between the vaccine and a group of children with brain damage, saw immunisation coverage drop to 30% in 1975 resulting in major epidemics in 1977/79 and 1981/83. As a result, there were more than 200,000 extra notifications and 100 deaths in 1970s and 1980s. Vaccine coverage steadily increased over the next decade as public and professional confidence in the vaccine was restored, reaching 95% by second birthday in 1995 and remaining at between 93% and 95% until 2010 when it increased to 96%. Correspondingly, overall notifications decreased dramatically during this period. The Health Protection Agency (HPA) initiated a programme of enhanced surveillance to monitor the number of cases of whooping cough and vaccine efficacy in 1994."
www.hpa.org.uk/Topics/InfectiousDiseases/InfectionsAZ/WhoopingCough/GeneralInformation/