Some children are immunocompromised or are allergic to a component within the vaccine and cannot be vaccinated. They rely on herd immunity to keep them safe and healthy. Image courtesy of Refutations to Anti-Vaccine Memes.
The vaccines cause autism thing is faked. Autism naturally comes out at that time. No-one actually proved that there was a correlation- the media got hold of a suspicion and hyped it up. Now learn this Science, and vaccinate your kids.
Anti-Vaxxers Reach New Low in Criticism of Autistic Sesame Street Character
And that study claiming vaccines are bad was admittedly altered & manipulated by the Dr that did it, who also as a result lost his license & was poised to make big bucks of of the fallout that that false report claim would've created.