A universal vaccine used to treat all known types of flu could be just around the corner after a major new discovery.
While healthcare agencies advocate for as many people as possible to receive their seasonal flu shot each year, millions of people across the world succumb to infections, with dozens dying each year in Ireland alone.
Now, new research published to Nature Communications by a team from the University of Pennsylvania suggests we are on the cusp of a universal flu vaccine capable of treating most known strains.
The candidate vaccine developed as part of this latest work was shown to elicit a strong antibody response to a structure on the surface of flu viruses – called the hemagglutinin (HA) stalk – when tested in mice.
If it were to pass clinical testing for use in humans, the vaccine could do away with the need for a seasonal vaccine, with a person only needing to take it a few times for the rest of their life.
“This vaccine was able to do something that most other candidate flu vaccines have not been able to do,” said the study’s co-senior author, Drew Weissman. “It was able to elicit protective responses against a conserved region that offers broad protection.”
Why seasonal vaccines are limited
Existing viral vaccines typically follow a method whereby viral proteins are grown in the lab to elicit an immune response in order to protect a person against future exposures to that virus.
When it comes to the flu, however, it hasn’t worked out so well because flu virus particles are studded with mushroom-like HA proteins, which seasonal flu vaccines use to evoke antibody responses.
The problem is that the antibodies are made to only target the HA ‘head’, which mutates rapidly and will soon be replaced by another strain.
However, the new vaccine doesn’t use flu HA proteins directly, but instead uses messenger RNA molecules that encode HA proteins to elicit an antibody response.
When injected into a person, 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 does a better job of mimicking a real flu infection and offers a very powerful protective antibody response.
Speaking of its potential, the study’s co-senior author, Scott Hensley, said: “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.”