Scientists said on the 18th that they found that they can fight against immune cells of all known influenza viruses. This 
"extraordinary breakthrough" allows experts to develop a single-dose flu vaccine.
Influenza is mainly seasonal, with hundreds of thousands of deaths per year, according to the World Health Organization (WHO).
Due to the continual mutation of influenza strains, vaccine formulations must be regularly updated and the protection currently 
provided is limited.
Australian researchers say there are "killer T cells" in more than half of the world's population, and the test proved to be 
effective against all general flu variants. This means that such cells may be used to develop a broad-spectrum influenza vaccine, 
the formulation does not need to be adjusted annually, and it is also effective for people who do not have such cells.
Marios Koutsakos, a researcher at the Doherty Institute at the University of Melbourne, said: "The flu virus is constantly 
mutating to avoid recognition by the immune system and is highly variable, so It is almost impossible to predict and vaccinate 
the virus strain that causes the next wave of influenza."

T cells are white blood cells that travel around the body to look for abnormalities and infections. T cells are vital to human 
immunity and are resistant to a large number of invading cells and viruses. The so-called "killer" T cells are unique and can 
directly attack and kill other infected cells.
Using the mass spectrometry to identify the same viral parts of all influenza strains, Kusamas and colleagues found that killer 
T cells are effective against influenza A, B and C variants.
The research team has patented their findings, and the researchers say they hope the cell will help them develop a broad-spectrum 
flu vaccine that "reduces the global impact of influenza and seasonal flu."