Two independent studies have devised a method to target multiple strains of the flu virus using a single vaccine. This universal flu vaccine strategy could soon prevent the need for seasonal flu shots. The Scripps Research Institute and the Janssen Pharmaceutical Companies of Johnson and Johnson collaborated on one of the studies, whereas the second study was conducted by the Vaccine Research Center, National Institute of Allergy and Infectious Diseases at the NIH.
The universal flu vaccine targets the part of the virus that remains unchanged across multiple strains
When designing a vaccine to a virus, features that separate the identification of one virus from another virus are built into the antigen. This process, though specific for that particular virus, renders the vaccine useless against slightly different strains of the virus. This is the case of our regular flu vaccines that need to be regularly updated because of minor-but-constant changes in their virulent strains. A hypothetical universal flu vaccine should therefore have a molecular characteristic common to most flu viruses, for it to be effective.
Vaccine uses the invariable parts of a commonly expressed protein called hemagglutinin
The influenza virus expresses proteins on its surface called hemagglutinins. These proteins are expressed in all subtypes of the flu virus, and are the virus’ gateway to the human cells. Mutations in this protein allow the virus to keep evading detection by vaccines. The hemagglutinins are tethered to the human cell with a stem-like region, which was discovered to be surprisingly unchanged across various strains. Scientists in both the studies therefore aimed at developing a vaccine containing the invariable stem region of hemagglutinin.
The vaccines were successful in rodents and nonhuman primates⎯a step closer to humans
In the Scripps study, the scientists successfully stabilized the hemagglutinin antigen without the head and delivered it to rodents and nonhuman primates. They found that the antigen elicited antibodies that bind to the vaccine components the same way they would bind a virus. This effect was seen over many subtypes of the virus, even in the bird-flu (H5N1) strain. The study at the NIH used a similar stem-specific antigen on iron nanoparticles to deliver the vaccine. They found a similar activity in mice and ferrets across flu subtypes and the H5N1 strain.
The prototype universal flu vaccine has so far shown remarkable effects in animals. Though, they have to undergo multiple trials in humans to be successful, this is definitely one step closer to a life-long protection from the flu virus.
Learn more about other universal flu vaccine strategies
Staying hydrated is the key to also staying healthy. Sometimes you just need a little reminder:
https://www.youtube.com/watch?v=mwnF1BfXqlA
Are We on the Brink of a Universal Flu Vaccine?
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