As thomas peebles jabbed a needle into the arm of a sick student in 1954, he told him, "Young man, you are standing on the frontiers of science." Indeed he was. Using blood collected at the boy's school, Peebles was able to isolate the measles virus, which John Enders then used to craft a vaccine in 1963. That year there were around 400,000 cases of measles in America. In the decade to 2013 the average number of annual cases dropped below 100. The disease is no longer endemic in America (though it still kills thousands abroad). The measles vaccine, now combined with those for mumps and rubella, is safe and effective. Yet some parents believe the opposite and refuse to vaccinate their kids. Some adults go unprotected, too. They reflect a rise in anti-vaccine sentiment fuelled by misinformation and pseudosci-ence. This has coincided with an increase in the number of measles cases in America, which hit 644 last year (see chart).
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