answer:There has been quite a bit of research. Most vaccines don’t have thimerasol. You certainly can space out the vaccines a little more than recommended if you like. I wouldn’t space out recommendations for series, but you can space out unrelated vaccines. You can check if your doctor is giving a brand that has thimerasol and ask for a brand that doesn’t have it. Again, very few vaccines have mercury, studies show the mercury was not the cause of autism, but if it concerns you you can avoid as much as possible. The other ingredient probably ate necessary or they wouldn’t be in there. Possibly, there are other ingredients that could be substituted, but I would think every ingredient in the vaccines have a reason did being there.