The newest COVID-19 vaccine approved for use, recently authorized by Canada, is made with plants.
“The plant that we use is Nicotiana benthamiana, it's a small Australian weed that’s a distant relative of the tobacco plant,” Dr. Brian Ward, the Chief Medical Officer of Medicago, said.
Medicago is a company producing plant-based vaccines and therapeutics.
“We deliver the DNA to the plant cell, that DNA makes mRNA in the plant cell, makes the protein in the plant cell, in the form of the virus-like particle. Then we harvest that virus-like particle and deliver the protein,” Dr. Ward said.
The vaccine is given in two doses, 21 days apart.
“The efficacy overall of our vaccine was around 70 percent, higher in protecting against moderate and severe disease,” he said. Dr. Ward said this vaccine is also the first plant-made vaccine that has been licensed for human use.
“The ability to harness nature for new medicines is really, really promising,” Dr. David Kroll, a professor of pharmacology at the University of Colorado Skaggs School of Pharmacy, said. Dr. Kroll has been studying drugs that come from plants throughout his career.
“In the past, we’ve developed vaccines from eggs. And those egg-based vaccines are great but they take a long time to develop. They are limited literally by the number of eggs available from the poultry industry,” he said.
Canada was the first to approve the vaccine in adults 18 to 62, purchasing 20 million doses so far. Dr. Ward hopes the U.S. is next.
“Our final package will go into the United States for licensure sometime in the very near future, the next month or two,” he said.
After that, the review process could take six to 12 months.
“Any time there’s a new production method, it takes a little longer for regulatory authorities to approve this new way of making a vaccine. And this is exactly what we saw with the pure messenger RNA vaccines,” Dr. Kroll said.
Having this new avenue for production is promising for the future of more than just the COVID vaccine. Medicago is also working on an influenza vaccine.
“What’s exciting about these different ways of making vaccines is we can respond much quicker to changes in viruses around the world,” Dr. Kroll said.