Coming soon: A "universal" jab that would protect against every type of flu, say scientists.
An international team is working on such a vaccine that will fight off all major strains of influenza - from the routine winter flu to virulent new strains of bird flu - and it claims that the jab could be available within a few years.
In fact, the scientists believe they have solved the problem of designing a "one fits all" jab using a new two-step approach to immunisation.
According to them, early safety trials of flu vaccine have already started and it could be tested on human patients as early as 2013, the British media reported.
Though the jab for humans is at an early stage of development, the scientists have tested it successfully on mice, ferrets and monkeys whose immune systems were "primed" with a "base" of influenza DNA.
In monkeys, they added a "booster" consisting of regular seasonal flu vaccine which increased and broadened its immunity. The vaccine's effectiveness would be improved each year until, recipients are immune to flu.
The "priming" or base vaccine came from a 1999 virus but antibodies were generated that neutralised viruses of different sub-types and from different years, the scientists wrote in the 'Science' journal.
"We are excited by these results. The prime-boost approach opens a new door to vaccinations for influenza that would be similar to vaccination against diseases as hepatitis, where we vaccinate early in life and then boost immunity through occasional, additional inoculations in adulthood.
"We may be able to begin efficacy trials of a broadly protective flu vaccine in three to five years," Dr Gary Nabel, the study leader from the US National Institute of Allergy and Infectious Diseases in Bethesda, said.