Tdap
Last week, I wrote about how conspiracy theories have been flowing fast and furious about the Zika virus and microcephaly. Even if you didn't see that post (perhaps instead having seen this one), you've probably seen the news reports describing how last fall the observation of a large number of cases of microcephaly, characterized by an abnormally small head and delayed brain development, in Brazil led researchers investigating the problem to suspect a link to a virus. That virus, the Zika virus, as you recall, is a mosquito-borne flavivirus related to dengue virus and transmitted primarily…