A new plant-grown influenza vaccine has been tested in two large-scale clinical trials, a first for vaccine research.
The vaccine contains the same virus-like particles as circulating influenza strains, which are extracted from an Australian tobacco relative that has been genetically instructed to create viral proteins.
The two trials involved nearly 23,000 people, and the results showed that plant-derived vaccines were not only safe, but also comparable to current commercial flu vaccines.
“To the best of our knowledge, these studies and the clinical development program that preceded them is the greatest demonstration to date of the potential of a plant-based platform to produce human vaccines. can be safe, immunogenic and effective, “the team wrote.
Every year, the vaccines that protect us against the flu must be renewed for the next flu season, which is a huge undertaking.
The flu virus is a species of chameleon, constantly changing the protein molecules it displays on its outer surface, and this leaves researchers eager to find ways to improve current vaccine technology. our own.
Most flu vaccines today are produced using virus particles grown and harvested from eggs or cells grown in a laboratory, taking months even after scientists. Find out what type of flu (and surface proteins) they need to target.
Plants, which can be engineered to make selective proteins and grown on a large scale, could be an alternative, helping to boost our seasonal flu vaccine production capacity.
This technique could also help overcome complications encountered in the current way of producing flu vaccines that sometimes make vaccines less effective.
In this system, the researchers used a relative of the tobacco plant in Australia, Nicotiana benthamiana, designed to create only the outer shell of the flu virus. These virus seeds are then extracted and purified under strict conditions to make a flu vaccine.
The researchers tested their plant-derived vaccine in two clinical trials, sponsored by the Canadian biotech company that developed the technique, and there were no major concerns about safety is reported.
This safety and efficacy phase III testing is often one of the last hurdles that vaccines need to remove before they can be approved for wide use.
But keep in mind that even if the flu vaccine is approved as safe and effective, any manufacturer needs to be able to produce millions of doses per year, which can present a challenge to consumers. vaccine factory.
The first trial involved more than 10,100 adults from Asia, Europe and North America, 18 to 64 years old, and it was designed to demonstrate that the vaccine could prevent 70% of people from becoming ill. testing to develop flu-like illness or other respiratory illnesses during a flu season.
Although it did not meet this high standard in the trial, the vaccine did protect about a third of people from influenza strains circulating in the 2017-2018 Northern Hemisphere in matching viral particles in this vaccine.
That may sound low, but the effectiveness of a commercial flu vaccine usually changes each year depending on how well the vaccine is suited to the different flu strains circulating that winter.
The researchers concluded, based on data collected in 2017-2018, that their plant-derived vaccines provided the same level of protection as commercial vaccines used during the season. That prolonged special flu, this is a fair outcome.
The second study recruited an additional 12,700 people aged 65 and over. This is quite important as the immune system of older people tends to weaken with age, making them more susceptible to infections.
“Like other flu vaccines, antibody reactions to [plant-derived] The vaccine also decreases with age, researchers say.
The plant-derived vaccine provokes less antibody response in the elderly, a somewhat desirable outcome, but it has triggered a significant increase in immune cells ready to respond to diseases. infections like flu.
Promisingly, the ability to protect people from flu-like illnesses during the 2018-2019 flu season remains on par with the commercially available flu vaccines used during that season.
“The field of plant-derived vaccines has grown tremendously over the past 28 years, since it was first demonstrated. [in 1992] that viral proteins can be expressed in plants, “said John Tregoning, an infectious disease researcher from Imperial College London. a commentary about the latest test results.
“This is the first time that plant vaccines have been tested in [human] “This is a milestone for this technology and the seeding of other plant-based vaccines and treatments,” said Tregoning.
If all goes well, one day, this research could give us another way to produce a seasonal flu vaccine that could also be expanded in the event of another flu pandemic.
In their paper, the researchers confirmed that their plant-based system could produce the first doses of a newly designed flu vaccine within two months of identifying a flu strain. emerging.
But there is still a long way to go to regulate regulatory approvals for this vaccine, so stay tuned for this space.
Research is published in Fingers.