while I do agree with tutuzdad that sticking a used needle into a
sterile insulin container is a very bad idea and to be honest, if I
were using the older method of separate insulin vial, syringe and
needle, I would probably never use the same needle, but in the newer
?pens? that are used today there would be a little amount of
contamination drawn back in to the insulin at the end of each
injection and changing needles would not alter that.
Other than that the only reference I can provide is personal and
contrary to what you are looking for.
Both my brother in law and i are type 1 diabetics with a combined
duration of almost 40 years.
For the last 5 years or so we have been using either disposable "pens"
or "disposable vials" pens, where you insert the needle into the vial
once and can use it to inject until that vial is emptied, or screw a
new needle on for every injection.
We both use short 10 or 15 mm needles and inject almost always (over
99%) in the stomach.
Even though, due to the local health care policy, we both have access
to as many free needles as we want but basically screw a new needle on
a new vial and throw them away together about a week later having been
used 10 to 14 times.
Neither of us has ever had an infection due to this, although the
needles do dull at the end of the week...
In pseudo clinical terms this would equal an experiment where 500 type
1 diabetics would each be asked to use his or hers same *personal*
needle twice or three times a day for a week with no infections
I have also been told both by my treating specialist and nurse,
officially, I was supposed to change needles foe each injection but
that, unofficially, almost none of their patients do that and that
they have had no known problems.
While there will probably be at least one documented case of an
infection occurring this way, I highly doubt a properly conducted
clinical experiment would find this a problem.