Every flu season comes with calls for vaccinations, and up until recently it was only the young and the old who were told to get their yearly immunization. A new vaccination needs to be given each year because of new flu strains that become prominent in the population every year. Flu viruses can mix and match DNA when they infect the same cell, creating a whole slew of new types of flu viruses when either a person or animal is infected with more than one strain.

For this reason, there has been much research into creating a universal influenza vaccine. The typical yearly flu vaccine has protection for three to four strains of virus, chosen by a team of experts. These experts determine which strains are likely to spread across the world during flu season and request that vaccine producers create the vaccine against those strains. Because between 3,000 and 49,000 people die yearly from the flu in the United States, finding a vaccine that protects for all strains would remove all the educated guess work.

Researchers in Boston from Sanofi, the French pharmaceutical giant, have published results in Nature on a new type of vaccine for the flu virus that is a step toward developing such a universal vaccine. A typical flu virus vaccine consists of the specific proteins hemagglutinin (H) and neuraminidase (N), which identify the flu strain. This can be seen in the naming of certain flu strains, like the H7N9 bird flu currently in China or the H1N1 swine flu a few years go. Scientists target these for vaccinations because they uniquely identify each strain of influenza, and vaccines can easily be made from them.

But in order to create a universal flu immunization, researchers are looking for parts of the flu virus that don't change between strains and from year to year. The typical flu vaccine takes months to make. Sanofi's new attempt uses a mixture of nanotechnology and biotechnology to create proof of a concept for a universal flu vaccine.

The researchers combined the hemagglutinin protein with ferritin, a protein found inside of human cells that naturally self-assembles into a biological nanoparticle. By adding the two proteins together, researchers were able to make self-assembling virus-like particles that could trick the immune system into a response similar to what is seen when people get infected with the flu or are vaccinated. "They look like flu. They react with [immune system] antibodies like flu," Dr. Gary Nabel, head researcher on the project, told NBC.

The experimental vaccine was injected into ferrets, as all flu vaccines must be tested on animals to assure that they induce immunity. After immunization researchers exposed the ferrets to multiple flu strains from 1934 until 2007, the animals showed high levels of protection. The vaccine even illicited protection from a 2007 variant of H1N1. The researchers stated that this vaccine was not designed as a universal vaccine so it did and cannot protect from all flu strains.

The method that the researchers used can reduce the time it takes to develop a flu vaccine from months to just under two weeks. Additionally, there would be no allergy concerns; with the current flu virus, people with egg allergies are cautioned when getting the vaccination or are directed to take an alternate version.

This new vaccine would protect against not only the seasonal flu variations, but also pandemic versions like bird flu-related viruses. Moreover, this technology would allow world health organizations and companies to develop yearly flu vaccines more cheaply, quickly, and in a more agile fashion than they currently do.

Source: Kanekiyo M, Wei C, Yassine H, etal. Self-assembling influenza nanoparticle vaccines elicit broadly neutralizing H1N1 antibodies. Nature. 2013.

Published by Medicaldaily.com