I think it's the content of the sites that turns people off. I.e., it's not just the messenger, it's the message. When I see an anti-vax website, I immediately

I think it's the content of the sites that turns people off. I.e., it's not just the messenger, it's the message. When I see an anti-vax website, I immediately dismiss it as just another anti-vax site. I imagine when an anti-vax person sees a pro-vaccination site, they feel the same way "Just another pro-vax site, and it's not going to address this serious issue that I saw on the anti-vax site." I'll accept an "appeal to authority", if I saw an anti-vax doc on the CDC's website, I'd definitely read it (critically). But since the "establishment" is so pro-vax, I suspect that the only authority an anti-vaxxer would accept is someone well known to be against vaccinations. It might be helpful if some of the parents groups that have been steadfast against vaccinations would reverse course when their children get the measles, but sounds like they are just digging in and dismissing the risk of measles.