As Australia’s flu season kicks off, scientists make a breakthrough

Scientists have edged closer to achieving a holy grail of medicine – a universal flu vaccine that does not need to be updated every year – thanks to a breakthrough led by Australian researchers.

Current influenza vaccines have to be reformulated every flu season because strains of the virus are constantly mutating. It can also be challenging to predict which strains are likely to dominate each winter.

An annual flu vaccine is recommended for all Australians aged over six months.Credit: Shutterstock

In a study published in Nature Communications on Tuesday, a team of scientists headed by Doherty Institute researchers outline their discovery of nine viral fragments of influenza B that – unlike other parts of the virus – do not change.

This brings the number of these discoveries to 27, offering a wider set of promising targets for a potential universal vaccine, the scientists say.

“Identification of those viral fragments that are unchanged in the virus’s history brings us a step closer to a broadly protective vaccine,” said Professor Katherine Kedzierska, head of the Doherty Institute’s Human T Cell Laboratory.

“Identification of such conserved (unchanged) regions is obviously the holy grail … the universal vaccine potentially would not require annual reformulation or annual vaccination, although occasional boosts might be needed.”

The researchers were excited to discover that the nine viral fragments provoked a strong immune response from killer T cells, a type of immune cell that can kill cancer cells and cells infected with a virus.

“They recognise small fragments of the virus, which remain unchanged throughout the viruses’ history,” said Tejas Menon, the co-first author on the paper.

“That’s why killer T cells are like ninjas of our immune response. They kill cells infected with the virus, but then after that they form immunological memory, so when the new virus emerges, even if it’s a mutated viral variant, those features can still be recognised and allow killer T cells to combat the next infection.”

Influenza B is particularly dangerous in the young, killing and hospitalising Australian children in 2023 after cases surged part way through the season.

So far in 2024 in Australia, influenza A has accounted for most flu notifications.

There were 33,325 cases reported to the National Notifiable Diseases Surveillance System between January 1 and April 7, a figure higher than in many preceding years. This could be partly to do with increased testing.

Thirty-one flu deaths have been reported.

David Tscharke, a professor of virology and immunology at the Australian National University, described the new research as a first step in the development of a universal influenza B vaccine.

“They’re not going to go back into the lab and make a vaccine that’s going to come out next year or the year after, but I guess this is the proof of principle.”

Tscharke also said killer T cells might only be part of the answer. He said that unlike the current generation of seasonal vaccines, which are good at stimulating antibodies in the blood and can stop the flu from taking hold, killer T cells didn’t provide the same immediate protection.

“What they are going to do … is help your body deal with that infection more effectively, so we’re really talking about a vaccine that may protect from severe disease. It’s not going to be a vaccine that stops infections.”

An annual influenza vaccination is recommended for every Australian aged over six months, and free vaccines are available for children aged six months to five years, pregnant women, people aged 65 and over, Aboriginal and Torres Strait Islander people and those with certain medical conditions.

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