Vaccines don’t cause autism — the science on the question is clear. But Donald Trump evidently thinks he knows better than the entire scientific community and took to Twitter to suggest otherwise...

The number of people who share of Trump’s view — which, again, is entirely unsupported by the relevant science — could be already be having pernicious consequences. For example, the U.S. is facing the worst whooping cough epidemic in 50 years, a disease easily prevented by vaccine. While budget cuts to state-level health organizations have exacerbated the epidemic’s spread, there are concerns that fears about the mythical autism-vaccine link are helping to increase the number of whooping cough cases as some children are not vaccinated.