Plant-based COVID vaccine is safe and effective

Medicago, a Canadian biotech company, has recently reported positive results from a large, late-stage clinical trial study of its new COVID-19 vaccine, which they developed in collaboration with the pharmaceutical company GlaxoSmithKline (GSK).

The phase three clinical trials showed a 75.3 percent efficacy against the Delta variant, with the vaccine’s overall efficacy rate against all variants (besides Omicron) being approximately 71 percent. What makes this vaccine unusual is that its key ingredient is grown in plants.  

“These are encouraging results given data were obtained in an environment with no ancestral virus circulating. The global COVID-19 pandemic is continuing to show new facets with the current dominance of the Delta variant, upcoming Omicron, and other variants likely to follow,” said GSK Chief Global Health Officer Thomas Breuer.

Medicago has already developed an experimental flu vaccine grown in Nicotiana benthamian, a plant related to tobacco. When the COVID-19 pandemic struck, they decided to use similar technology to produce a vaccine against the coronavirus. The vaccine uses virus-like particles to mimic the structure of the coronavirus, without actually containing genetic material from the real virus.

In March 2021, the company started the late-stage clinical trials, with over 24,000 participants aged 18 or above from the United States, Canada, the United Kingdom, Brazil, Mexico, and Argentine. The results were highly promising. “We had about 74%-78% efficacy to prevent moderate and severe disease,” reported Medicago medical officer Brian Ward. When taking into account milder cases too, the vaccine had a slightly lower efficacy, close to 70 percent.

In terms of side effects, Ward said, “pretty much everybody gets a sore arm.” This is probably due to the fact that the vaccine uses an adjuvant produced by GSK in order to rev up the immune response. However, less cases of fever and other side effects were reported than for other types of vaccines. Moreover, another advantage of the new vaccine is that it does not require special freezers to store it, such as Pfizer’s or Moderna’s vaccines.

Medicago plans to ask Canadian regulators to authorize their vaccine as soon as possible. If this application will be successful, they will immediately start distributing the 76 million doses promised to the Canadian government. 

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By Andrei Ionescu, Earth.com Staff Writer