Researchers from the University of Washington have designed and developed a DNA-based vaccine which could potentially replace annual flu vaccinations in the next ten years. The research, published in PLOS One late last year, is the result of over a decade of development and also involved the design and production of a novel DNA delivery system, dubbed the ‘Gene Gun’.

Annual flu shots, a vaccination that many people have each winter to protect them against the influenza virus, are not always effective as a preventative measure. It’s estimated that they are between 40 and 60% effective each year, although this percentage can vary significantly; the last two years, for example, have seen the vaccine fail for many people. One reason for this is that the scientists tasked with producing the vaccines have to predict the flu virus most likely to threaten patients roughly 9 months before flu season begins.

The chances of this prediction being wrong are increased by the fact that viruses can mutate very rapidly and unpredictably. This means that the viral components targeted by each vaccine may not be present in the most prevalent virus strain that year, inactivating the drug.

To combat this, the research team from the University of Washington designed a DNA-based vaccine which targets the genetic components of the virus that do not change from year to year. The vaccine involves inserting novel DNA sequences into the patient’s cells that can teach their body to recognise and attack the viral DNA.

The team also had to identify a way in which their DNA vaccine could be delivered into patient’s cells, and this led to the development and production of the ‘Gene Gun.’ The machine emits a painless ‘puff’ of DNA into the skin, where it is directly taken up by skin cells and incorporated into the genome. In this way, the actual vaccine can be produced within the body by human cells, instead of inside a petri dish.  

“Your own skin cells end up producing these antigens and stimulate the immune responses,” said Deborah Fuller, PhD, lead researcher and Professor at the University of Washington.

The DNA vaccine was tested in non-human primates exposed to the previous influenza strain, with a 100% success rate. It is important to note that the sample size was very small (consisting of 8 macaques), but these preliminary results are promising. The team also tested the vaccinated animals with a novel flu strain, which also elicited an immune response.

There is much more work to be done before this vaccine could become available to the public. For instance, the approach has not yet been tested in humans and the team are still working on a clinical prototype for their Gene Gun. Nonetheless, the team are hopeful that their work will progress in the near future and believe that the vaccine may reach patients within the next ten years.

“This is a new concept in flu vaccines, it’s going to be the new wave of vaccines, the ‘Universal Flu Vaccine’, it’s our future coming down the line,” said Dr Fuller.