http://www.nps.org.au/__data/assets/...s_vaccines.pdf

This from the National Prescribing Service a great Australian independent reference on the efficacy of Medications.

I wouldn't say less of something is better, only if it is effective with smaller doses.

As always cost is everything, with governments it's tender processes. With GP's it how good the price is, the number of samples and how good the free pens and coffee scrolls are!!!