The message explaining the lack of evidence surrounding an alleged link between vaccine and autism was found to have helped to reduce parents' misconceptions, but only decreased the intent to immunize among those with the most negative views on vaccines.
Among those parents who received the message with the images of children affected with the vaccine-preventable diseases, belief in a vaccine-autism link only increased, according to the study.
“Current public health communications about vaccines may not be effective,” the study concluded. “Attempts to increase concerns about communicable diseases or correct false claims about vaccines may be especially likely to be counterproductive.”
Diseases such as measles that once killed hundreds and infected thousands each year were all but eliminated by 2000 because in large part to yearly vaccination requirements for schoolchildren.
But cases of measles have been rising in recent years in areas of the country where child immunization rates have fallen below levels needed to achieve “herd immunity,” where the number of those vaccinated is high enough to maintain public safety against infection for the entire population.
In 2013, the number of reported cases of measles in the U.S. was nearly three times the annual average of 60, according to the Centers for Disease Control and Prevention. The majority of outbreaks of the disease that occur can be traced to people who contracted the disease outside the U.S. and brought it into this country who spread the disease to people who were not vaccinated, experts say.
Follow Steven Ross Johnson on Twitter: @MHsjohnson