Have scientists finally created a jab to keep ALL flu strains at bay?

A universal vaccine that protects against all strains of the flu virus may be one step closer.

The annual flu vaccine currently protects against four strains of the virus that scientists believe are likely to be in circulation by next winter.

But a vaccine that protects us against all types of flu – which kills between 10,000 and 30,000 people a year in the UK – is one of the holy grails of medicine.

There are three different types of flu viruses that affect humans – A, B and C, with different subtypes (including only 29 of type A) that can mutate over time.

Scientists look at flu patterns in other parts of the world to help decide which strains to include in the annual flu vaccine given here — but that has to be months in advance to allow time for the vaccine to be made.

The vaccine includes two A strains and two B strains that are believed to be most likely to circulate in the coming winter (type C strains are not included, as they usually cause only mild symptoms).

But scientists don’t always have the right selection. In 2014/15, for example, the flu shot was only 3 percent effective in preventing flu cases because the strains in the vaccine were so out of balance with what was circulating.

In 2015, nearly 30,000 people died from flu and pneumonia in England and Wales alone, compared to 25,000 the year before.

Now, by taking a new approach, scientists at the US National Institute of Allergy and Infectious Diseases have taken a “great step forward” in the search for a universal flu vaccine. Current vaccines target the “head” of proteins called hemagglutinins, which are located on the surface of the flu virus. This ‘heading’ varies between strains and changes over time – which is one of the reasons why the vaccine needs to be updated every year.

The new research focuses on the ‘stem’ of the protein. Since this is sufficiently similar between different species, it is theorized that this provides protection against all species.

To get the immune system to focus on the stem and not the head (as programmed by previous flu vaccines), scientists chopped off the head and replaced it with an engineered head that the body’s immune system wouldn’t recognize.

“The only thing the immune system can see is the stem,” says Sarah Andrews, an immunologist and one of the researchers.

To test this new approach, involving only the influenza A strain, 52 volunteers were injected with two doses of the experimental vaccine. The hope was that this would provide protection against all A strains of the virus.

The results showed that the vaccine appeared to be safe; about one-fifth of recipients experienced injection site pain or headache, consistent with the side effects reported with the standard flu shot.

A year after being vaccinated, the participants still showed antibodies to all type A flu strains, the journal Science Translational Medicine reported last month.

The new vaccine includes two A strains and two B strains that are believed to be most likely to circulate in the coming winter (type C strains are not included, as they usually cause only mild symptoms). [File image]

The next phase will be to conduct clinical trials to see if such a vaccine actually protects people against flu and extend it to influenza type B. If successful, a universal vaccine could be available within five to ten years , the scientists said.

Will Irving, a professor of virology at the University of Nottingham, described the initial findings as ‘very encouraging’.

“Historically, the flu virus has been a very difficult target for vaccine manufacturers because of its ability to change the structure of its outer layer,” he says.

“Progress towards a single vaccine that could elicit protective immunity against the wide range of influenza virus variants that exist in nature would be a major step forward.”

Andrew Preston, professor of microbiology at the University of Bath, adds that while the trial results are only preliminary, “it suggests that this approach is well tolerated in humans, produces a robust immune response and that the response persists for well over a year.” . It’s still early days, but these are the results we need to see from an early phase trial.’