About Me

When not at work with students, I spend my time in my room either reading, calculating something using pen and paper, or using a computer. I read almost anything: from the pornographic to the profound, although my main interests are mathematics and physics. "When I get a little money I buy books; and if any is left I buy food and clothes." -Erasmus

Saturday, January 22, 2011

Blog Comments and Vaccination

I've been reading Orac's blog, and I've been entertaining myself (as well as procrastinating) by reading the comment thread. It's a lot of fun because it's uncensored, and you get to see how perfectly nasty (in a good way) some people can be. It's a case of schadenfreude-- it's enjoyable reading how trolls get nuked by other readers; it's also nice to see that the comments include links to evidence (articles in peer-reviewed journals).

His blog seems to be the kind that draws a lot of fire from the anti-science mainstream in the U. S.; it's terribly disappointing to see how bad science education is in the U. S.  I recall A Private Universe, a video where Harvard students (arguably considered the brightest in the United States) were asked about the origin of the seasons, and they failed to answer such a basic question correctly.

I probably wasted half of the afternoon just reading the comments, and following up on the cited papers. I also learned, for example, about the vaccination rates at various kindergarten schools in California. One of the statistics that intrigued me is the connection between vaccination rates and the rates for PBE's (or personal belief exemptions, where a parent has to sign an affidavit asking that his or her child be exempted from vaccination).

One of the worries of  the pro-vaccine camp (of which I am a member) is the reduction of herd immunity. Vaccines are never 100%  effective. There is still some chance that you can get infected if you get exposed to the pathogen, and the vaccine didn't take. More vaccinated people reduces the likelihood of being exposed to the pathogen, so getting vaccinated is also a good thing for your neighbor.

On the other hand, if you live in a region where most people aren't vaccinated, you are more likely to catch the disease compared to those living in areas of high vaccination rates. So it makes sense to look for pockets where many people are not vaccinated, because they would be most at risk. So I looked at the vaccination rate data in Californian kindergartens.

One of the stats on the California Department of Public Health is the PBE rate; high PBE rates mean parents are opting out of immunization. The recommended immunization rates for herd immunity is greater than 90 percent, and I see schools where more than 50 percent of parents opt out. This means not enough immunizations for herd immunity, and it's no surprise when outbreaks do occur at these places.

Another statistic I noticed was the how often Waldorf schools get on the list of kindergartens with PBE's greater than 50 percent. Coincidence? I immediately thought of outbreaks at such schools, and unhappily found out that I was right to suspect that outbreaks would occur at these schools. In fact, they have occurred.

I then read news items on Waldorf schools, and found that there's actually a journal article Eurosurveillance, Volume 15, Issue 26, 01 July 2010 , in which an outbreak of measles is associated with a Waldorf school. I also saw news items on outbreaks involving other Waldorf schools. A search on google using the keywords: outbreaks Waldorf school (without parentheses) will give you a host of links.

Waldorf schools, by the way, are expensive private schools, and it's downright alarming to find supposedly well-educated well-off parents not getting their kids immunized. It's almost as if they're waiting for an outbreak. By then, of course, it would be too late.

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