This question already has an answer here:
I found this claim among a survey of anti-vaxxers reported on qz
60% of anti-vaxxers describe their political leaning as liberal:
Much of the other profile characterics reported there aren't surprising at all e.g. "88% more likely not to have seen a doctor in the past year", low income and education etc., but the one about political orientation struck me as unlikely. Are there other surveys like this and do they agree or disagree with one on the political orientation of anti-vaxxers?
I've looked at the actual Pew report linked in the story and I can't see the breakdown of anti-vaxxers by any of the characteristics in the qz story (maybe it's in the raw data, I haven't checked that.) The qz story says "CivicScience extrapolated a series of indicators to help understand their profile", and then gives the quoted claim, so that data doesn't seem to come from Pew.
So why would this matter distribution-wise? Less than 25% of Americans actually identified as liberal in 2015 (the year of the qz story). Only 42% of Democrats and respectively 7% of Republicans identified as liberal in same year, according to Gallup. So assuming these two surveys didn't diverge on how they asked about the political orientation (was the there a "moderate" answer possible in the qz CivicScience poll?) then we would know something about a correlation/concentration of anti-vaxxers. And it would be puzzling considering that, in contrast, liberal Democrats are the leading group in trusting scientists in other matters like climate change.