<p>Apparently, from February 4 to February 7, a student living in Contra Costa County with measles rode BART and attended classes at Berkeley, potentially exposing BART riders, as well as other students and instructors at Berkeley.</p>
<p>People don’t get vaccinated any more?</p>
<p>I have to assume the person was either from another country or homeschooled. Maybe there are medical reasons for not having the vaccine, but where I am, to be in public school, you have to show you have been vaccinated. I wonder if there were likely to be enough people on the train who weren’t vaccinated to really even spread it.</p>
<p>California has had a personal belief exemption from vaccination requirements. A minor change was made for 2014, but it is not difficult for the anti-vaccine people to avoid vaccines: <a href=“New California Law Requires Doctor's Note For Vaccine Exemptions... But There's An Out | KPBS Public Media”>http://www.kpbs.org/news/2014/jan/02/new-law-requires-doctors-note-vaccine-exemptions-c/</a> . But obviously such a change is not relevant to when the student was a child when he would normally have gotten the vaccine against measles.</p>
<p>Unfortunately, there are enough anti-vaccine people around that one cannot rely on herd immunity if one has a medical reason for being unable to get a vaccine (such as allergy to a vaccine ingredient), or who do not seroconvert to immune status after receiving the vaccine.</p>