The whole scare about thiomersal is purely theoretical, and isn't based on science. There is a fundamental difference between the stereotypical "mercury" seen in poisoning, vs the mercury in thiomersal. In thiomersal, the mercury is rendered inert. Furthermore, there's been large scale studies looking at thiomersal, and there is no association with things like Autism, etc.
The whole thiomersal fear-mongering really hurt vaccine science and public opinion, pressing people into becoming mindless Jenny McCarthy's over it.
I've mostly seen it in that regard as well, don't get me wrong.
There are some studies that do demonstrate inorganic mercury deposits in tissues after the breakdown of ethylmercury (which is a metabolite of thimerosal). It is NOT as significant, or as dangerous, as the amount of mercury one would get if that metabolite were methylmercury, this is true - and that original fear, that ethylmercury and methylmercury were essentially the same, is what drove the FDA to recommend the cessation of thimerosal use in vaccines. It was then thought that that was misplaced and unfounded, and that ethylmercury was actually very safe.
However, as I stated, I've seen some studies that seem to be about demonstrating that ethylmercury is not nearly as dangerous as methylmercury (with specific mention of Thimerosal) - however, it also comes with point-blank acceptance that yes, raw, inorganic mercury, the same deadly Hg we've always known, is still a metabolite of ethylmercury. It seems methylmercury is one of the metabolites of ethylmercury, which may be way mercury is a metabolite - and why there is LESS mercury, with a shorter half-life in the body, than when you do start with methylmercury.
If that shorter timeframe in the body, and lesser amount, is still reasonable to you - that's fine and all, but I think it's time for a different preservative. When you learn that a preservative deposits potentially dangerous mercury into your body (which crosses the blood-brain barrier, btw), that should be cause for concern.
That said, it's also possible to ingest small amounts of mercury and still be fine... theoretically. Many toxic things can make themselves known to your body, and you don't suffer for it at all.
Or we do, and it's just so minimal it's difficult to ever place how and why you started becoming a different person.
Whether it can ever be linked to autism is an entirely different subject of research - toxicity of mercury, however, is not up for debate. You can play the odds and are likely come out 100% fine - but it's still an unnecessary risk.
Again, this is not about being anti-vaccine, of which I'm not, as I still get them. It's about smart science - evidence suggests it could be potentially harmful, at least at the "right dosage" - but we're not mature enough in our scientific knowledge to truly determine how often we can be exposed to microscopic dosages before it causes a change in the genome or crosses a few neurons (in a manner of speaking). So you may not receive a confirmed toxic dose of mercury when getting a rare multi-dose vaccine with thimerosal in it - but, can we determine how often we can receive 25μg* of Hg before it's not exactly doing us any favors?
*25μg is the typical mercury content of a single-dose of influenza vaccine that has been pulled from a 5.0mL multi-dose vial of Novartis's Fluvirin.
Most single-dose vaccines have zero thimerosal, and no mercury. Most of us will only ever see single-dose vaccines if we go to get a vaccine somewhere. It might be different at any kind of mass clinic, but I can't recall the last time I ever saw multi-dose vials.
BTW, if you want a vaccine but don't want one from a vial and will refuse to receive if given such, do realize they also make single-dose vials (0.5mL). Yuu can get a single-dose pre-filled vaccine, or they take a generic syringe and often use a single-dose vial.
[edit: This
Source goes here.]