In 1998, a paper was published claiming that the measles-mumps-rubella vaccine caused autism. In response, thousands (tens of thousands? hundreds of thousands?) of parents have refused to have their children vaccinated against those diseases and others. That has led to unnecessary disease among children, some of which undoubtedly were affected mentally or died. Researchers spent time looking at the vaccines and the way they are produced to try to find a causative agent, with no such agent found. Their time and effort could have been spent in productive ways.
The waste is enormous, and this news needs to be spread widely.
The paper was supposedly based on a sample of only twelve children, which should have raised questions early on, but the media and frightened parents quickly raised the claim to doctrine.
It's not true. Never was. The paper was fraudulent, the data manipulated by a doctor who was hired to help win a lawsuit.
Here's the full story. There's a summary in a box at the end.
Some thoughts on why and how a story like this can propagate. One of the points in this article is that a risk will seem more threatening if it seems to come with little benefit. Numerous times, when I've been arguing against the anti-vaccine viewpoint, it's occurred to me that in some degree, the vaccines themselves are responsible: they have prevented terrible diseases that people now have no experience of, like polio, whooping cough, diphtheria, measles, mumps, and rubella. Having heard from my mother of her choking with diphtheria (and losing two siblings to it) and seeing polio epidemics every summer, the cost-benefit was always obvious to me. But the vaccines have worked so well that most Americans have no such close experience of these diseases.
More links here.