It was developed by PATH as part of the solution to the problem of delivering vaccines to areas which have insufficient medical workers to meet the needs of traditional, doctor-mediated vaccination programs.
After that, with "a firm, rapid motion" the needle shield would be pushed into the port until the "gap between the needle shield and port closes completely".
Almost simultaneously, the reservoir would be pushed down in a similar motion to opening a blister pack or using a syrette, dispensing the medication through the needle into the skin.
[original research] The device, once used, should be considered sharps waste.
The introduction of the Uniject has been called "the greatest single leap forward in the battle against tetanus"[4] because it has allowed tetanus vaccines to be used in places which were previously inaccessible to health programs.