New York, Jan 25 (IANS): A new vaccine developed using nanoparticles offers universal protection against several influenza A viruses such as H1N1, H3N2, H5N1 and H7N9, researchers say.

Influenza, a contagious respiratory illness that infects the nose, throat and lungs, is among the leading causes of death, according to the Centres for Disease Control and Prevention.

The new vaccine provided immunisation, complete protection against lethal virus exposure and dramatically reduced the amount of virus in the lungs to mice exposed to several influenza viruses.

"Vaccination is the most effective way to prevent deaths from influenza virus, but the virus changes very fast and you have to receive a new vaccination each year," said Bao-Zhong Wang, Associate Professor at the Georgia State University.

"We're developing a universal influenza vaccine. You wouldn't need to change the vaccine type every year because it's universal and can protect against any influenza virus."

Instead of targeting the exterior head of hemagglutinin (HA) -- the virus's surface protein -- as traditional seasonal flu vaccines do, the new vaccine targets the inside portion of the HA protein known as the stalk.

The stalk is more conservative and offers the opportunity for universal protection.

However, because the stalk domain itself is not stable, the researchers assembled this stalk domain into a protein nanoparticle as a vaccine.

"Once inside, the nanoparticle can protect this antigenic protein so it won't be degraded. Our immune cells have a good ability to take in this nanoparticle, so this nanoparticle is much, much better than a soluble protein to induce immune responses," Wang said.

The nanoparticles are unique because they were generated to contain almost entirely the protein capable of inducing immune responses, the researchers said, in a paper published in the journal Nature Communications.