This outbreak is demonstrating two things - disease outbreaks happen in "pockets" of unvaccinated children, and, those "pockets" are often found in Waldorf/Steiner oriented institutions (for a comprehensive critical introduction into Anthroposophy, read the three part series on DC's Improbable Science blog). Indeed, the last whooping cough outbreak I personally saw was in the Steiner Kindi in two streets down from where we lived in Germany. The daycare director interpreted the outbreak as "the children seeking disease, because they needed a break" and proposed to close the Kindi for three weeks (a plan curbed by the working moms whose children attending the facility had been vaccinated and were just fine). What a break that was, with several children needing a 3 week residential rehab to learn how to breathe normally again... I'd rather pay money for a break than health, but that may be just me.
Similarly, quite impressive measles outbreaks in (mostly German speaking) countries have started in Steiner schools and Kindergartens and were sometimes specifically centered around Anthroposophical doctors with an
The good news is that school and parents are complying with the suggested quarantine and/or treatment measures to limit transmission. Hopefully, some of them will research the "crunchy, holistic" philosophy behind their school and their vaccine refusal a bit more carefully, too.