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Universal flu vaccine has promising clinical trial results

A universal flu vaccine, that is, a flu vaccine that could protect against multiple strains, regardless of annual mutations, is the unicorn of vaccines. Instead of yearly flu shots to account for new influenza virus mutations, the universal flu vaccine could protect against the flu over a number of years.

I know many people ignore the seriousness of the seasonal flu. They think it’s nothing more than a cold (it isn’t, symptoms are completely different), and that the flu isn’t dangerous (it is, killing hundreds of thousands of people across the world every year). And although the flu is most dangerous for infants and seniors, it can attack the young and healthy.

This new vaccine has shown promising results in a new clinical trial that has just been published in a peer-reviewed medical journal.

As I usually do, let’s look at these new results.

person holding thermometer
Photo by Polina Tankilevitch on

What is a universal flu vaccine?

This is a flu vaccine that is effective against all influenza strains regardless of the virus subtype, antigenic drift, or antigenic shift. This means that the vaccine should not require new versions from year to year, as we do now.

The universal flu vaccine targets conservative antigens on the flu virus that don’t change frequently and are found on all flu viruses. Current flu vaccines target antigens of the influenza virus that change often (sometimes yearly), so your immune system is not adapted to new mutations of the virus.

Several new universal flu vaccines are under development and in clinical trials.

Universal flu vaccine clinical trial

The clinical trial results were published on 27 July 2023 in Lancet Infectious Diseases. The researchers examined the immunogenicity, safety, and effectiveness of the OVX836 vaccine, under development by Osivax in Lyon, France.

OVX836 is a recombinant H1N1 nucleoprotein vaccine. Nucleoprotein is a relatively stable protein in viral particles — not prone to the mutations that change surface antigens so often that new strains are constantly emerging. Presenting this stable protein as an antigen could reduce the need for constant flu vaccine updating.

The study was a Phase 2a randomized, double-blind, placebo-controlled study that included 137 healthy adults aged 18–55 years in a single center in Belgium.

The key results were:

  • The vaccine effectiveness was 84%, with four cases of influenza A in the 33-patient placebo group, and two cases among the 104 patients who received the vaccine.
  • The vaccine had a good safety profile and tolerability. No serious adverse events were observed.
  • There were no dose-limiting toxicities at the highest dose.


This is a small phase 2a study that needs to be confirmed with a larger cohort (several thousand) of individuals in a phase 3 study. This will give us better information on the proper dose of the vaccine and potential adverse events.

Also, another clinical trial is underway for individuals 65 years and older, since they often have different immune reactions to vaccines.

We really need a universal flu vaccine because it can be a challenge to get people to get their flu vaccine every year. I do, but if I could have a vaccine that lasted years or even decades, I’d be the first in line for that.

Obviously, we are early in the development cycle for this new flu vaccine. But I’m optimistic we will get one in the upcoming few years.


Michael Simpson

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