Approaching A Universal Flu Vaccine?

Every year, public health departments and health agencies engage in the grueling process of convincing people to get a flu shot. Every year people refuse: The vaccine doesn’t work! I got the vaccine and still came down with the flu. Why do I have to get it every year? I hate shots!

What if we had a vaccine that protected us against all different strains of flu? What if this vaccine protected us for more than one flu season?

Researchers from the National Institute of Allergy and Infections Diseases (part of the National Institutes of Health) are helping us get there. Author Gary J. Nabel et al recently published results of research on their new flu vaccine in mice and ferrets. They had some pretty encouraging results: The new flu vaccine produced 34 times more anti-flu antibodies in mice and ten times more anti-flu antibodies in ferrets than traditional flu vaccines do; the new vaccine protected against multiple flu strains, and researchers hypothesize, based on results, that it could protect against future strains of H1N1 that have not yet emerged.

The flu virus is notorious for its ability to mutate rapidly; the last year’s vaccine is often ineffective by the next season. Each year, scientists try to predict what varieties of flu will most likely circulate among the population and then create a vaccine based on their estimations. Whether or not the predicted strains actually show up determines what the effectiveness of the vaccine appears to be.

The team, which included representatives from Sanofi, the National Institutes of Health and AstraZeneca’s biotech unit MedImmune, created their vaccine using a 1999 strain of H1N1. The vaccine is made of self-assembling nanoparticles. Eight hemagglutinin (a protein found on the surface of the influenza virus, and the “H” in flu names) fragments are attached to a ferritin protein (a protein that transports iron) to create a new molecule somewhat resembling the flu virus (to give credit where credit is due, Ed Yong describes this whole process in a blog post for Nature). The new flu vaccine was designed so that the immune system is trained to recognize a part of the virus (hemagglutinin) that is common to all strains and subtypes, regardless of whether they mutate. One advantage of this nanoparticle is that it doesn’t require the same arduous creation process that the traditional flu vaccine does. The ferritin makes it somewhat self-assembling. This eliminates the need for growing viruses in egg cells and cultures.  

Currently, vaccines are grown in eggs, a slow and expensive process. When outbreaks occur, the time that it takes to produce new vaccines means more illness and deaths from flu. The new vaccine is instead produced in a lab and can be made much more quickly. Researchers estimate that it would take about one to two weeks.

Flu vaccines work by teaching the body’s immune system how to fight an infection. The current or traditional vaccines contain a weakened version of the virus. When the immune system recognizes the virus, it produces antibodies, which destroy the virus. Then, when someone is infected with a stronger flu virus, the body has these antibodies ready.

However, if the flu virus mutates, which it does quickly and often, the body will not be able to recognize it anymore. This is why doctors recommend that people get a flu vaccine every year.

Researchers agree that, while this is an important first step towards reimagining vaccines, a different vaccine would still be needed for each subtype of virus from H1 to H17. Influenza viruses are divided into three type groups, A, B and C, with A and B causing the most outbreaks. Influenza A viruses are named for the type of two proteins on their surface, hemagglutinin and neuraminidase. There are 17 different “H” and 10 “N” options. Each of these subtypes then has different strains, which are typically named for the year that they are identified. Influenza B viruses do not have different subtypes but do have different strains.

The next step for this vaccine is clinical trials with people to see if it produces such a strong immune response in people as well as animals. If the flu vaccine is successful, researchers hope to start creating similar types of vaccines for HIV, herpes virus, and coronavirus among others. 

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