From the awesome STATS (Statistical Assessment Service) blog, which follows the use of statistics in the media:

“A new and fascinating study in the journal Pediatrics examines what happened when an intentionally unvaccinated seven-year old boy caught measles on a trip to Switzerland in January 2008 and brought it back to San Diego. Despite the city having a 95 percent  immunization rate, clusters of intentional under-vaccination, particularly in upper income and private school enclaves, led to the largest outbreak of measles in the city since 1991. 839 people were exposed to the disease, which sickened 11 other children, 8 of whom were unvaccinated, apparently due to parental fears of adverse vaccine effects or the misguided belief that “natural lifestyles” would confer protection (the other three were too young to have been vaccinated).”

STATS quotes MedPage Today, which printed an abstract of the study (which is all we get to read online for free), saying that the primary infected or “index” child:

“directly infected his two siblings, two classmates, and four children who were treated at the same clinic. The index patient’s sister then infected two of her classmates. One of the index patient’s classmates infected his brother, bringing the total number of cases to 12.”

According to MedPage, “a vigorous outbreak response” by city health officials prevented further transmission, but it came at a cost of $176,000 or $10,000 per case (including the cost of quarantining infants too young to be vaccinated).

We really do need to figure out how to address the fears of parents who still believe, all evidence to the contrary, that vaccines cause autism or other problems more serious than, oh, measles, mumps or rubella. We scream at cross-purposes — those who forgo vaccines are selfish ignoramuses putting all of us at risk, while those of us who favor vaccines are blind shills for drug companies — but it’s vital we learn how to address the anti-vaccinators’ concerns. Hectoring them isn’t helping. As shown among the ultra-Orthodox in New York and in Israel, measles is increasingly common because of parents choosing not to vaccinate. I have friends who believe their natural lifestyle is sufficient protection. Is it that they don’t know, or forget, or think it’s irrelevant that measles can lead to pneumonia, encephalitis, corneal scarring, even death (particularly in people with compromised immune systems)? I’m not sure. That’s why I think public health officials should be researching WHY these folks believe what they do and what would be the best way to reach them. Because the consequences of our failure are dire. STATS paraphrases MedPage’s report that docs are concerned that:

“the size and number of unvaccinated clusters and that herd immunity will not prove a bulwark against the transmission of disease, especially to infants who haven’t yet received their vaccinations.  What is most troubling is that such clusters were most likely to occur among white, well-educated, and well-to-do parents.”

I only have a few friends who don’t vaccinate, and it’s such a sore subject we can’t really address it. I’ve chosen the friendship over useless dreying. (I know, maybe I shouldn’t.) I hope real science-y people can figure out how best to reach the anti-vax holdouts, since I obviously can’t.