What is the recent findings about autism and vaccinations?

I am confused at what to do. I hear such mixed evidence out there re: whether or not I should vaccinate my son. He is 11 months old and is due for his MMR next month. I do believe in vaccinations but I also read so much about a possible link between vaccinations and autism. Not to mention my nephew was fine until his one year vaccination and now is autistic. I might choose to wait until his immune system is stronger. Just wondering what I should do….