This is atrocious and disgusting.
But, sadly, I'm not surprised. The antivaxx movement is deeply mixed with antisemitism, as are all conspiracy theories. That's one thing they all have in common. It's always, always the Jews' fault.
Here in Sweden the antivaxx movement is a strange concoction of people from way different movements: new age, alternative health, antisemites, right wingers, nazism, conspiracy theorists, science deniers, you name it.
It's probably the same in every country.