Scientists at the Doherty Institute have identified nine new similarities between different types of the influenza B virus, which can be particularly dangerous for children.
Killer T-cells in the immune system each reacted strongly to those nine fragments, which lead researcher Katherine Kedzierska likened to a "target" for future vaccines that aim to fight off all forms of the flu.
"The findings are significant as they pave the way for the design of potential vaccines," the University of Melbourne and Doherty Institute laboratory head told AAP.
She said identifying parts of the virus that did not change was the "ultimate goal in the quest for a universal influenza vaccine".
"Such vaccine would potentially not require annual reformulations or vaccinations, although occasional boosts may be needed as we age or for those with underlying health conditions," Professor Kedzierska said.
"We would perhaps not need to get vaccinated annually but periodic boosting every five or 10 years."
The study was published in prestigious journal Nature Communications on Tuesday.
Doherty Institute graduate researcher Tejas Menon said it involved sifting through hundreds of virus fragments in collaboration with Monash University scientists.
"Before our study, 18 of these unchanged influenza B viral fragments had been identified but with our study, we brought the total up to 27 ," Mr Menon said.
"So there's more options for a potential future influenza vaccine."
Prof Kedzierska said it would be difficult to put a timeline on any future work and explained that understanding how T-cells recognised viral variants could increase understanding of other viruses.
She said the findings should serve as a reminder for Australians to get vaccinated before the flu season.
"The current influenza vaccines are still the best way we can combat annual epidemics," she said.
"This is especially important for individuals in high-risk groups, including the elderly, pregnant women and people with comorbidities."
Authorities have recorded 42,000 laboratory confirmed cases of the flu in Australia so far in 2024 and more than 289,000 cases in 2023.