From herd immunity and complacency to group panic: How vaccine scares unfold

Apr 05, 2012

Worries over vaccine risks can allow preventable contagious diseases, such as measles and whooping cough, to make a comeback. A new study, published in PLoS Computational Biology, shows how to predict ways in which population vaccinating behavior might unfold during a vaccine scare.

"These findings might help in evaluating and developing global and ", said Professor Chris Bauch of the University of Guelph's Department of Mathematics and Statistics.

Prof. Bauch and Samit Bhattacharyya of the University of Utah developed a mathematical, "Behavior-incidence" based on and social learning. They tested the model with real data from two infamous vaccine scares in England and Wales: the 1970s outbreak and the measles-mumps-rubella vaccine scare in the 1990s. In both cases, the publication of alleged vaccine risks was followed by a media firestorm in national newspapers, television, and radio. In light of this, the fact that it took 4-5 years for vaccine uptake to bottom out was puzzling. They found that the model could explain the patterns of the vaccine scares very well, and could also be applied predictively to the data sets.

The model captured the interplay between disease dynamics and vaccination behaviour during those episodes. One of the theoretical dynamics for the model was the phenomenon known as "herd immunity"; an entire population—including unvaccinated individuals—can be protected from infection by vaccinating only a certain percentage of the population. This suggests that immunization programs can be victims of their own success as past vaccinations drive disease incidence to such low levels that unvaccinated individuals feel no incentive to get vaccinated, creating ideal conditions for vaccine scares and thus future outbreaks.

Due to these conditions, as Prof. Bauch says, "Vaccine scares could become more common as eradication goals are approached for more vaccine-preventable diseases. Such models could help us predict how vaccine scares might unfold and assist in mitigation efforts."

Explore further: 'Moral victories' might spare you from losing again

More information: Bauch CT, Bhattacharyya S (2012) Evolutionary Game Theory and Social Learning Can Determine How Vaccine Scares Unfold. PLoS Comput Biol 8(4): e1002452. doi:10.1371/journal.pcbi.1002452

add to favorites email to friend print save as pdf

Related Stories

Cholera vaccine could protect affected communities

Nov 27, 2007

A vaccine used to protect travelers from cholera, an infection characterized by diarrhea and severe dehydration, could also be used effectively among those living in cholera-prone (endemic) areas, according to a research ...

Recommended for you

Affirmative action elicits bias in pro-equality Caucasians

18 hours ago

New research from Simon Fraser University's Beedie School of Business indicates that bias towards the effects of affirmative action exists in not only people opposed to it, but also in those who strongly endorse equality.

Narcissistic CEOs and financial performance

Jul 24, 2014

Narcissism, considered by some as the "dark side of the executive personality," may actually be a good thing when it comes to certain financial measures, with companies led by narcissistic CEOs outperforming those helmed ...

Election surprises tend to erode trust in government

Jul 24, 2014

When asked who is going to win an election, people tend to predict their own candidate will come out on top. When that doesn't happen, according to a new study from the University of Georgia, these "surprised losers" often ...

User comments : 0