Thankfully, scientists are working on a universal flu vaccine. The study, published in the Science journal, said the new vaccine triggered high levels of antibodies in all tests and may help reduce the impact of future flu pandemics. This vaccine packs the mRNA recipe of all known H and N protein variants into the shot instead of fragments of proteins from 4 to 5 strains of influenza virus found in the typical seasonal flu shot. Given the RNA being smaller in size than protein, they could pack four into one vaccine, meaning no more annual flu shots!
So far, scientists have shown success in mice and are now at the clinical trial phase — the final step before going to market.
Vaccines are a form of artificial immunity that functions like a training module for your immune system. If your immune system was the Karate Kid, think of a vaccine as it's very own Mr Miyagi! Many vaccines are specific to a certain antigen, a piece of biological material that functions as an identification marker for your immune cells.
Generally speaking, manufacturers cover only a handful of influenza virus strains in each year’s production. The strains typically included in a dose of the shot are based on which influenza variant is most prevalent that year.
Is the flu virus just one variant? Nope! Influenza comes in different varieties. The virus has two main surface proteins which our immune system recognises. You may find strains of influenza viruses named in the format of a letter and a number, e.g. H1N1. This is due to each influenza virus having some variation of the Haemagglutinin (H) and Neuraminidase (N) surface proteins.
Let's consider H1N1 "swine flu" strain. It has the Haemagglutinin variant 1 and Neuraminidase variant 1. This means to the most effective flu shot you can get against H1N1 is vaccines that are specific against H1N1. If your flu shot vaccinates you against H4N1 or H1N5, it may be less effective than the H1N1 shot, given only 1 surface protein is matched. An H4N5 vaccine would be useless against H1N1 infections as there are no matched antigens.
Influenza can mix their genetic material around when two different strains of influenza virus co-infect a host. When someone catches the flu from both the H1N1 and H4N5 flu virus, they can now spread up to 4 influenza variants — H1N1, H4N1, H1N5 and H4N5. Influenza LOVES to mix around its segmented genes.
Considering the speed of the SARS-CoV-2 vaccines, universal flu vaccines may be here within the decade.