Today in the US and a growing number of other countries, the official policy is that any scientific study, regardless of its methodology, quality, author credentials, and peer-reviewed process is summarily dismissed as incomplete, irrelevant or unsupported if it finds a connection between any vaccine or combination of vaccines and autism spectrum disorder.
Read this article for more info:
http://www.greenmedinfo.com/blog/new-vaccines-still-cause-autism-and-our-government-knows