Flu vaccines typically protect the person against three to four influenza viruses that are common during the winter season. According to the CDC, there are many different flu vaccines manufactured that are licensed and approved by the United States Food and Drug Administration (FDA).
For the first time, a new flu vaccine is made from plants that have been put to the test in two large-scale clinical trials which have proven that it can match the commercial vaccines available.
This plant-based vaccine has virus-like particles that resemble the circulating flu strains from native Australian tobacco plant relatives that were genetically modified to produce the viral proteins.
Constantly improving flu vaccine for the next season
In contrast to cell cultures or eggs, plants are one of the world's most prolific protein producers. They efficiently express proteins of varying complexities and glycosylation patterns. They can also be engineered to produce specific proteins and cultivated at scale, thus becoming an alternative to help boost the capacity to creating seasonal flu vaccine.
The new plant-based flu vaccine underwent two large-scale trials which nearly reached 23,000 participants when combined. The results suggest that the vaccine is both safe and could fairly compete with commercial flu vaccines, Science Alert reported.
The research team wrote that their studies and clinical development are the largest demonstrations so far of the potential for a plant-based flu vaccine that can be safe, immunogenic, and effective.
Since every year flu vaccines are needed to be upgraded for the next flu season, vaccine development is indeed a huge undertaking. Researchers are feverishly looking for new ways to improve their vaccine technology because the influenza virus is like a chameleon that is constantly changing its protein molecules that it displays on its outer surface.
Tobacco plant-based flu vaccine
The researchers used Nicotiana benthamiana, an Australian relative of the tobacco plant, to produce the outer shell of influenza viruses which are then extracted and purified under strict conditions to make a flu vaccine. The vaccine needs to pass Phase III of vaccine development to be deemed safe and effective.
After the first trial is conducted in Asia, Europe, and North America, they found that the vaccine protected two-thirds of the participants from the flu strains circulating in those areas from 2017-2018 during the winter season. The result may sound low but take note that flu vaccines usually vary from year to year based on the flu strains present during that season.
Nonetheless, the first trial involving more than 10,000 people has proved that the tobacco plant-based vaccine is safe and as effective as the commercial vaccines available.
Moreover, the second trial with more tha 12,000 elderly participants was conducted and was found to activate a substantial increase in immune cells. Like the first trial, it also proved to be safe and effective like the vaccines available today.
"This is the first time a plant vaccine has been tested in a [human] clinical trial," infectious disease researcher John Tregoning added. "It is a milestone for this technology and sows the seeds for other plant-based vaccines and therapeutics."
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