A flu vaccine injection that is given just once in a lifetime and can fight off all strains of the virus will be available within the next five years, according to findings presented at a Royal Society conference.
The vaccine would fight not only the winter flu that leaves millions feeling miserable each year, but also deadly pandemic viruses.
The current flu jab protects roughly 75% of those immunised and needs to be reformulated each year to keep on top of changes in the virus.
The new drug, developed at the National Institute of Health (NIH) in Maryland, US, uses DNA to trick the body's immune system into producing antibodies against the "lollipop stick".
Unlike the head, the "stick" changes little from strain to strain, which means one vaccine should protect against multiple strains of the virus. The vaccine was also effective against bird flu.
Safety trials have begun on people and its effectiveness could be tested on patients by 2013. If the vaccine is successful, it could be in widespread use by 2015.