HQ Team
November 25, 2022: Come winter and people are recommended to get their flu shots. The annual flu vaccines are effective against certain strains only as the virus is constantly evolving. Now researchers at the University of Pennsylvania have created a vaccine that is effective against all 20 known strains of influenza.
The vaccine trialled on animals developed antibody responses against all A and B influenza strains. The vaccine uses the same messenger-ribonucleic acid (mRNA) technology as successful Covid vaccines.
mRNA has genetic codes for making proteins, and the vaccine mRNA encodes fragments of proteins found in all 20 known strains of influenza.
This has raised hopes of a universal flu vaccine.
The strains have different versions of two proteins on their surface, haemagglutinin (H) and neuraminidase (N), which are targeted by immune responses. But even within one strain, there can be slight variations in these proteins, so the version in the universal vaccine will not exactly match every possible variant.
In tests in mice, the team found that the animals generated antibodies specific to all 20 strains of the flu virus, and these antibodies were active up to four months.
In another test, the team gave mice the universal flu vaccine or a dummy vaccine containing code for a non-flu protein. A month later, they infected them with either one of two variants of the H1N1 flu virus, one with an H1 protein that was very similar to the version of the protein in the vaccine and one with a more distinct version.
All the mice given the flu vaccine survived exposure to the virus with the more similar protein, and 80 per cent survived being infected with the more distinct variant. All mice given the dummy vaccine died around a week after infection with either variant.
Another group of mice were given an mRNA vaccine targeted only to the precise flu strain they were exposed to, and all of this group survived over the same time period.
This suggests that a universal flu vaccine would not be as effective against new variants of the 20 flu strains than an annual vaccine matched to new forms of the virus, according to some experts. But they agree that the animal data are promising and thus a good indication of what will happen in humans.
“The idea here is to have a vaccine that will give people a baseline level of immune memory to diverse flu strains,” Dr Scott Hensley, one of the scientists behind the work at the University of Pennsylvania, said.
“There will be far less disease and death when the next flu pandemic occurs.”
The research is available in the journal Science.
