The return of this scourge has been driven by one factor in particular: misinformation, spread by vaccine critics, that scares parents into not immunizing their children.
Along with rumors that vaccines cause autism or that the trace amounts of mercury and aluminum in them are dangerous — falsehoods that were long ago debunked — have become innuendos aimed at deeply religious parents. …
As New York’s current measles outbreak has spread, the more obscure ingredients of the measles vaccine — which is often delivered in a shot mixed with vaccines against mumps, rubella and chickenpox — have become an issue for some Orthodox Jews.
(The New York Times, April 26, 2019)