A universal flu vaccine with a strong antibody response, that could protect people against most influenza strains, is one step close to reality, a study has revealed.
 

Experiments performed on mice showed that the vaccine elicited a strong antibody response to a structure on the surface of flu viruses, called the hemagglutinin (HA) and protected them from infection by various flu strains. Unlike the seasonal flu vaccines that are updated every year, the new vaccine can also 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 study co-senior author Drew Weissman, Professor at the University of Pennsylvania in the US. "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," added Scott Hensley, Associate Professor at the varsity.

The findings are described in the journal Nature Communications. As opposed to the seasonal flu vaccines, the new vaccine does not directly use flu HA proteins, instead, it uses mRNA molecules that encode HA proteins to elicit an antibody response. 

When injected into a recipient, these RNAs are taken up by immune system dendritic cells and translated into copies of the HA protein by the protein-making machinery within those cells. This within-cell production of viral proteins does a better job of mimicking a real flu infection and elicits a very powerful protective antibody response, the researchers explained.

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