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A Canadian biotech company reports positive results from a large-scale study of its COVID-19 vaccine. What makes it unusual is that the main ingredient of the vaccine is grown in plants.
Medicago has already developed an experimental flu vaccine in Nicotiana Benthamian, a tobacco related plant. When the pandemic hit, the company decided to try and make a COVID-19 vaccine.
Now it seems those efforts have paid off.
“This is an incredible moment for Medicago and for new vaccine platforms,” Medicago CEO and President Takashi Nagao said in a statement.
Vaccines work by showing the immune system something that looks like a virus, but isn’t. By doing that, the immune system can prepare for the event that the real virus should show up.
In the case of Medicago, the vaccine look-alike is something called a “virus-like particle” produced in plant cells that have been given genetic instructions to make the coronavirus spike protein.
The new results come from a survey of more than 24,000 volunteers in six different countries. Half received the vaccine, half a placebo. When the study reached about 165 cases of COVID-19 among the participants, it prompted a review of the results.
“We had about 74%-78% efficacy to prevent moderate and severe disease,” Medicago medical officer Brian Ward told NPR.
The vaccine fared slightly worse, closer to 70% efficacy, when looking at all cases of COVID-19, including milder ones.
Medicago vaccine has been tested against variants
But there’s something important to keep in mind, according to Ward. The Medicago vaccine is based on a virus-like particle that resembles the original strain of the virus.
“All the cases in this study were caused by these new variants,” he said.
Most cases were either the delta or gamma variants. Omicron had not yet arrived at the scene when the investigation was conducted. Ward says other vaccines have also had lower efficacy in fighting the variants.
As for side effects, Ward says, “pretty much everyone gets a sore arm.” He says the sore arm is likely due to something called an adjuvant, which is added to the vaccine to boost the immune response. The adjuvant that Medicago uses in its vaccine is made by GSK.
One thing the vaccine researchers saw very little was the fever that sometimes accompanies other COVID-19 vaccine shots.
No need for ultra-cold freezers
An advantage of the new vaccine is that it does not require special freezers to store it. Standard cooling is sufficient.
Medicago plans to ask Canadian regulators for permission to distribute its vaccine. Meanwhile, they are preparing the vaccine stocks.
“We currently have commercial lots that are bottled,” says Ward.
But production capacity is a problem. At present, the plants that make the virus-like particles are grown in North Carolina. Ward says he’s confident they can deliver the 76 million doses they’ve already promised the Canadian government. And he says the company is building a new facility with a much larger capacity.
“And if we still have a COVID problem at the end of 2023, our large global facility in Quebec City will come online,” Ward said.
Unfortunately, the world could indeed still be left with COVID-19.