Scientists have moved a step closer toward developing a universal vaccine against seasonal influenza, which can cause severe illness and occasionally death. The concept for the vaccine grew out of a natural experiment during the 2009 global flu pandemic.
The process for developing a protective vaccine against the sometimes deadly viral infection is imperfect at best. The problem, say experts, is that drug developers are always trying to stay one step ahead of the pathogen, as they attempt to predict which of a number of circulating viral strains is going to emerge as the dominant one that year.
Currently, vaccines contain proteins from several strains, designed to produce antibodies to stimulate a protective immune response. But the virus continuously mutates, so a vaccine cocktail is not effective after one flu season.
Imperial College of London Chair of Infectious Diseases Ajit Lalvani says British researchers have drawn the blueprint for a universal vaccine against all varieties of influenza.
Killer cells are key
Instead of stimulating antibody production, Lalvani says the new vaccine would ramp up production of CD8 killer T cells, immune system cells that attack core influenza proteins, which are the same in all strains of the virus.
“Such a vaccine would induce T cells that would be able to recognize new viruses that have not even been identified yet. In other words, future pandemic strains. In that sense, it’s a universal vaccine. And it will be different to existing vaccination where currently every year a new vaccine has to be developed, which is why we are always one step behind,” said he.
Lalvani and colleagues proved CD8 T cells could be used as the basis of a universal vaccine by recruiting some 350 staff members and students in the autumn of 2009 during the start of the flu pandemic.
The participants donated blood samples and were given nasal swabs. Every three weeks, they answered questions about their symptoms. If they fell ill and experienced any flu symptoms, they used the nasal swabs and sent them to a laboratory for testing.
Researchers found those with the most severe symptoms had the lowest T cell counts, while those who caught the flu, but had very mild or virtually no symptoms had the greatest number of CD 8 cells.
Lalvani says this “natural experiment” provided researchers with the ingredients to make a universal flu vaccine.
“Since we know what the components are, we know what T cell needs to be induced, we really have the design of the vaccine in hand. It’s now a matter of producing it and carrying out clinical trials to confirm safety and effectiveness,” says he.
Lalvani predicts that a universal flu vaccine will become available within the next five years.
on a universal influenza vaccine was published in the journal Nature Medicine