In 1956, a team of social scientists led by Leon Festinger finished a book called When Prophecy Fails. Sixty years later, this book is still considered a classic in the field. It introduced a concept called cognitive dissonance, a theoretical model that helps to explain how humans do or do not change their minds when faced with contradictory information.
In the book, Dr. Festinger followed a doomsday cult that had spun off from the early Scientology movement. The premise of this cult was that the world would end by a flood on December 21st, 1954, but that a flying saucer would come rescue the true believers and take them to safety. As astute readers will likely guess, the world did not end that day, and cult members were forced to make sense of the fact that their closely held belief was not true.
I won’t spoil the book – it is easy to find for those with a taste for mid-century academia – but a few points should help summarize. First, in the immediate aftermath of the failed prophecy, the cult modestly shifted focus, and claimed that they saved the world through the power of their beliefs. They responded to the cognitive dissonance by creating a story where they were the heroes. Second, the group became more insular and even more devoted after the non-event, in part likely due to the scorn of others around them.
As you are likely aware by this point, the nation of Samoa is undergoing one of the most deadly measles outbreaks in a small population in modern history. This tragedy is still ongoing, though a massive public health response is beginning to take shape. As of December 2nd, there had been over 4000 cases and 60 deaths.
The seeds of this outbreak were planted in 2018 when two babies died after receiving measles vaccination. This tragic error occurred when two nurses somehow used a muscle relaxer instead of water to dilute the vaccine. Anti-vaccine activists pounced on this tragedy, sharing it around the internet as evidence that pediatric vaccines are more dangerous than medical authorities admit. Vaccination in the island nation was suspended for nearly a year.
In June of this year, Australian anti-vaccine activist Taylor Winterstein attempted to hold a vaccine workshop in the capital of Apia (it was canceled due to pressure from Samoan officials). Other anti-vaccine activists reportedly visited the country in the past year, including Robert F. Kennedy Jr. Months prior to the current outbreak, public health officials were expressing concern about the damage that these activists could do in such a vulnerable population. [1, 2] By the beginning of the measles outbreak in October, only 31% of kids under 5 were vaccinated against measles, down from an estimate of 84% four years ago. 
As predictable as this measles crisis has been, the response of the anti-vaccine activists should surprise no one either. The prominent US anti-vaccine voices – Del Bigtree, RFK Jr, Andrew Wakefield, Suzanne Humphries, etc – have been curiously silent when asked their opinion. The more strident activists of the social media world have taken the When Prophecy Fails strategy, and doubled down on their anti-vaccine activism, while taking bizarre credit for helping to stop the outbreak. For instance, one group has been sneaking into hospitals to start vitamin therapies and attempt to talk people out of vaccination. Weirder yet, some activists are actually blaming the vaccination effort (which started weeks after the outbreak) for the disease.
Speaking of predictions, I think it is important for vaccine advocates to make a few of them at this time. In the past two weeks, a global response has led to a staggering 60,000 doses of measles vaccine – enough to cover nearly a third of the population – administered. There has not been a comparable rapid vaccination event in modern history, so we are getting front-row seats to a unique field test of vaccine safety and efficacy.
Because of this effort, we are likely to see:
- The number of new cases of measles should start to peak and decline by year-end or shortly after as the vaccine-induced immunity starts to take effect
- No new problems in the population that were caused by the vaccine (e.g., autism/asthma/autoimmunity rates stay static in the population)
- The mortality rate over the next decade will be lower in the children vaccinated against measles than those who suffered from the infection.
If any of these predictions are wrong, especially the second, it will require a rethinking of our current worldwide measles control strategy. If all three are right, however, it will add to the consistent and overwhelming body of evidence that our current vaccine policy is effective with minimal individual risk.
Dorothy Martin, the cult leader featured in When Prophecy Fails, lived until 1992, and reportedly was still communicating with aliens and prophecizing doom until her end. I don’t expect that the events in Samoa will change the minds of many hardcore anti-vaccine activists, either, but they will likely expose their beliefs for their dangerousness, inconsistency, and tone-deafness.