725
Ultrasound can push vaccines into the body without needles
(www.newscientist.com)
This is a most excellent place for technology news and articles.
My favorite anecdote, though not necessarily mine, about jet inoculation comes from the army. They had long lines of men to immunize and little time to do it. Walk up, hold still, hear the click, feel the water pierce you, walk away sore. However, if anyone moved even slightly during the process, the needle of water becomes a knife, slicing their shoulder open. It was not a well thought out mechanism.