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Searching for a universal flu vaccine

Microscope image showing human cells infected with the flu. Image from UCBL1, Lyon. © Inserm/Rosa-Calatrava, Manuel & Ressnikoff, Denis
Microscope image showing human cells infected with the flu. Image from UCBL1, Lyon. © Inserm/Rosa-Calatrava, Manuel & Ressnikoff, Denis

Researchers may have found ways to make a vaccine against all strains of the flu virus, potentially saving millions of lives.

Last year’s flu vaccine rarely works on this year’s strain due to the virus’ very high mutation rate. Worldwide, the seasonal flu virus causes 3 to 5 million cases of severe illness and a further 250 000 to 500 000 deaths every year.

A pandemic flu strain could kill millions in the months it would take scientists to make a specific vaccine.

Three separate EU-funded projects are now developing techniques to teach our immune systems to recognise any flu strain, removing the need for scientists to develop new vaccines each time a new strain appears.

The four-year EDUFLUVAC project is planning to produce a universal flu vaccine suitable for clinical trials by the time it finishes in 2017. While current flu vaccines use one component from the H1, H3, and B flu virus strains, the EDUFLUVAC project will use multiple components from each strain, in order to teach the immune system about the similarities between different strains, producing a broader immune response.

Dr Ed Remarque, an immunologist at the Biomedical Primate Research Centre in the Netherlands, compares it to teaching children what a car is. ‘You show them many different versions of a car to learn what a car is,’ he said. ‘If you show them only one car, they may believe that all cars are red.’

It means that if the immune system sees many strains of flu, it can focus on the similarities and ignore the differences, allowing it to eventually recognise strains it has not yet seen.

This approach was inspired by Dr Remarque’s previous work on developing a malaria vaccine, but the idea of exposing the immune system to multiple strains of the same virus was first suggested by Davenport and Hennessey in the United States in 1957. ‘We are now 57 years down the line and Davenport’s paper from 1957 is really up to date,’ Dr Remarque said.

The goal of the project is to have a universal flu vaccine that would ‘at least provide five years of coverage,’ though problems such as waning immune responses over time may reduce the period of effectiveness.

The vaccine will be sold on a non-profit basis in the developing world, a result negotiated by the European Vaccine Initiative, which is supporting the EDUFLUVAC project. In the developed world, it will be specifically targeted towards high-risk groups such as elderly people and school-age children.

Future strains

The surface proteins the flu virus uses to invade healthy cells are mushroom-shaped. While the ‘heads’ of the proteins are highly susceptible to mutations, the ‘stems’ are less changeable from one generation to the next, giving antibodies a way to target them.

The FLUNIVAC project, which runs until late 2017, is using this knowledge to produce a different type of universal flu vaccine.

‘Maybe we are already covering future virus strains.’

Dr Tim Beaumont, Senior Scientist, Aimm Therapeutics

By producing antibodies that recognise the stems of the flu surface proteins, the vaccine can ‘neutralize a whole bunch of (flu) viruses,’ explained Dr Tim Beaumont, Senior Scientist at Aimm Therapeutics, a private partner on the project.

This type of vaccine may also neutralize viruses that are now present only in birds and not yet in humans. ‘Maybe we are already covering future virus strains,’ he said.

The project has already produced the antibodies required and future work will involve testing the effects of the vaccine. Similar to the EDUFLUVAC project, FLUNIVAC aims to have a universal flu vaccine ready for early stage clinical trials in four years.

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