Potential universal flu vaccine identified

Scientists have identified a potential universal influenza vaccine that could protect people against most strains of the virus.

The candidate vaccine, described in the journal Nature Communications, elicited a strong antibody response to a structure on the surface of flu viruses, called the hemagglutinin (HA) stalk.

It protected mice from infection by various flu strains, researchers said.

It has the potential to be developed into a universal flu vaccine, which -- unlike the current seasonal flu vaccines -- could be given a few times over a lifetime to provide protection potentially similar to a tetanus vaccine.

"This vaccine was able to do something that most other candidate flu vaccines have not been able to do," said Drew Weissman, a professor of at the University of Pennsylvania in the US.

"It was able to elicit protective responses against a conserved region that offers broad protection," said Weissman.

"If it works in humans even half as well as it does in mice, then the sky's the limit - it could be something that everyone uses in the future to protect themselves from the flu," said Scott Hensley, an associate professor at University of Pennsylvania in the US.

Modern viral vaccines typically use lab-grown viral proteins to elicit an immune response that protects people against future exposures to a virus. On the whole, this approach has not worked well against influenza viruses.

Seasonal flu vaccines provide incomplete and temporary protection against the flu. This is why they need to be updated every year.

The vaccine does not use flu HA proteins. Instead, it uses mRNA molecules that encode HA proteins to elicit an antibody response.

"When we first started testing this vaccine, we were blown away by the magnitude of the antibody response," said Hensley.

The team observed that after immunisation, these strong antibody responses to the vaccine persisted through the thirty weeks of the experiment.

In addition to the mice, the researchers successfully repeated these experiments in ferrets and rabbits, other species commonly used as vaccine-development animal models.