Developing a universal flu vaccine?

Every year, experts develop a new vaccine to best combat the coming annual flu wave, based on the previous year's virus and others expected to arrive. Developing a vaccine that meets its mark, however, is a true challenge.

The year 2010 presented major challenges because scientists have only limited experience in dealing with flu seasons following a pandemic such as the outbreak of swine flu in many countries in 2009. The complexity of flu transmission in the Southern Hemisphere compounds the difficulty of predicting which virus will emerge as the most predominant in, say, Norway.

The vaccine that Bionor Pharma's scientists are developing will be less dependent on which form the various flu viruses take.

Triggers immune cells

"Vaccines for seasonal flu consist of virus particles based on the virus that is expected to predominate," explains Maja Sommerfelt, Chief Scientific Officer at Bionor Pharma. "But the vaccine we are developing uses only the particles that are common to all type-A flu viruses, in people as well as animals." Dr Sommerfelt heads a flu project that receives funding under the National Programme for Research in Functional Genomics in Norway (FUGE), one of the Research Council's Large-scale Programmes.

In this way, the vaccine will provide basic immunity to all of the most common flu viruses. It is also expected to have a long "memory" so that people do not need a new vaccination each year.

The vaccine will also work in a different way from other flu vaccines. Typical seasonal flu vaccines block the virus by triggering an antibody response. Bionor Pharma's vaccine, however, allows the virus to invade the cells, which are then quickly destroyed by the immune system -- preventing the virus from spreading.

"So we may become infected," says Dr Sommerfelt, "but the vaccine triggers our immune cells, which quickly seek out and kill the infected cells. The virus factories are removed, so to speak, preventing the illness from spreading throughout our body. We don't become as ill as we otherwise would."

She believes the vaccine will save lives and yield positive social and economic benefits. Fewer people will have to stay home from work to recover -- or to tend to their infected children.

Inspired by HIV vaccine

The idea for a new kind of flu vaccine arose in connection with the company's research on an HIV vaccine.

"Like the flu virus, HIV is a highly variable virus, appearing in many forms. Amidst all the concerns about a flu pandemic during the 2005-2006 outbreak of avian influenza," recalls Dr Sommerfelt, "it occurred to us that the flu virus may be a good candidate for the type of vaccine we were developing for HIV."

Viruses contain proteins, and both the HIV and flu vaccines that Bionor Pharma is developing are based on tiny protein fragments called peptides. When a cell becomes infected, it expresses these peptides outside the cell, which alerts the immune cells to come and destroy that cell.

The genetic composition of every known flu virus worldwide is stored in databases, including information about the various viral proteins.

"We analysed amino acid sequences in all the proteins to determine the areas they share in common," continues Dr Sommerfelt. "Next we researched how we could alter these sequences so that they would stimulate the immune system in the greatest proportion of the population."

Several years to go

She believes a universal flu vaccine will also help to prevent pandemics, which occur when a completely new flu virus emerges that is highly contagious and resistant, spreading rapidly across the globe.

"If an entirely novel virus should emerge, it would take a long time to develop a pandemic vaccine. Fortunately, last year's swine flu did not take the serious turn that was feared. Had that outbreak been more powerful, though, it would've been nice to have a peptide vaccine to provide some basic immunity."

Dr Sommerfelt stresses that much remains to be done before we can go to the doctor for a peptide flu vaccine that will remain effective for several years or seasons. Vaccines must undergo three lengthy clinical testing phases. She and her colleagues are also investigating other, non-injection-based ways of administering the vaccine, with an eye to mass immunisation.

"It will take at least seven to eight years before we have a vaccine on the market," says Dr Sommerfelt.

In the meantime, we can only hope that the human immune system can tackle the viruses on its own, or cross our fingers that this year's seasonal flu vaccine hits the bull's eye.