A flu jab that is given just once in a lifetime to fight off all strains of the disease is expected to available within five years.
Described as the "holy grail" of flu research, just one or two shots could provide lifelong protection, a conference held by the Royal Society, Britain's most prestigious scientific body, heard.
The current flu jab protects only three-quarters of those vaccinated and needs to be reformulated each year to keep on top of changes in the virus.
It targets a lollipop-shaped head of a protein that sticks out from the surface of flu particles. The protein is key to infection but the head constantly mutates, meaning it differs from strain to strain.
The new drug, developed at the National Institute of Health in Maryland, uses DNA to trick the body's immune system into producing antibodies against the protein's base instead - the "lollipop stick", reports the Daily Mail.
Unlike the head, the "stick' changes little from strain to strain, meaning one vaccine should protect against multiple strains of the virus.
Dr Gary Nabel, the institute's director of vaccine research, used the DNA from the protein to trick animals' immune systems into producing antibodies that seek out and destroy the bug.
He then gave a "booster shot" of a harmless flu or cold virus to ratchet up the immune response.
This primer-booster approach killed off a flu virus from 2007 and one from 1934, despite the DNA coming from a strain that circulated in 1999.
Mice and ferrets - creatures seen as good predictors of the human course of flu - both fought off potentially deadly flus with the help of the double jab.
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 as safe and powerful as the research team hope, it should be in widespread use by 2015.