My biggest issue with the multi-dose ones are that if there is a reaction you will have no idea what it was to. I also think it masks to parents how much is actually being injected into their children. "Three needles" doesn't sound as bad as "seven vaccines" all at once.
Where I live DTaP-IPV-Hib is standard, and given along with Pneumoccocal and Meningalcoccal. Even if I were to vax, there is no way I would give all of that at one time, to a two-month-old infant, no less.
ETA: I have never actually done the math to see if the adjuvants/aluminum/preservatives/various other crap in multi-doses are actually greater than the sum of its parts. My research led me down the road to no-vax instead of selective vaxing, so it was never a decision I had to make. Something to carefully look into and consider though if you decide to vaccinate.
I'm confused about the difference between single and multi dose vaccines. I hear people say that the single dose ones are safer, but I can't seem to find any information that explains why. Our pediatrician only gives single dose vaccines and he says there is no aluminum in them, which I doubt. Can anyone enlighten me?
The difference between a single dose vial and multi-dose vial is simple. All multi-dose vials contain thimerosal, which contains mercury. In the United States, most vaccines now are only supplied in single dose vials. A big exception is flu vaccines. The majority of available flu vaccine doses come from multi-dose vials. Another exception is some tetanus and meningococcal vaccines.
The purpose of the thimerosal (mercury) in the multi-dose vials is to kill the bacteria that is introduced into the vials as a result of more than one needle insertion into the vial. Multi-dose vials contain 10 doses, so each needle insertion is a chance for contamination to occur.
I think the multi-dose vials are probably popular for flu shots from a supply chain perspective. Millions of doses must be distributed rapidly. One multi-dose vial of flu vaccine is equal to ten prefilled syringes. The drug company has to fill and label all those syringes and put them in a cardboard box with ten little individual compartments. This takes more time and resources for the drug company, and takes up more space to store and ship. Versus filling one vial and putting it in one box. I would be very surprised if multi-dose vials were not, as a consequence, significantly cheaper for the immunizing organization, and they also take up less space to store once they are at their destination. True, the immunizers need to procure their own syringes and needles, instead of only needing the needles for the prefilled syringes. But syringes are cheap as crap and you don't have to store them in the fridge, so this isn't a big deal. The only drawback from a logistical standpoint, as discussed by above posters, is the burden on the immunizer to draw up the shot from the vial, and the potential for error introduced at this step.
Personally, as an immunizer, I like prefilled syringes for this reason, since they are much easier for me to work with. It doesn't take THAT long to draw up a shot from a vial, true, but over the course of multiple shots that time really adds up, and I have a lot of other demands on my time as well. I do idly wonder if the amount of money my employers save on the multi-dose vials is offset by the cost of our time to draw up the doses.
We get single-dose vials of some vaccines, and those annoy me! If we're going to get a single dose, it would be so much easier to have it in a pre-filled syringe, and the one I'm thinking of is available in that form.