A new technology makes injections pain free, as it relies on a laser instead of a hypodermic needle to deliver medicine.  The laser based system is currently being using by dermatologists for facial aesthetic treatments, but it could be implemented for vaccines soon.  The laser works by sending microscopic jets of the drug through the skin with a puff of air.  The injector can precisely control the depth of injection and amount of medication delivered.  Read more here.

Image from nj.com