A research team succeeded in producing the glycoprotein Spike of the coronavirus in Plant and combined it with a adjuvant named AS03 to form their vaccine candidate. To test its efficacy and safety, an international phase III randomized controlled trial placebo was conducted in 85 centres. Their results were published in the prestigious journal The New England journal of Medicine (NEJM) on May 4, 2022.
Half of the patients included received two placebo injections while the other half received two shots intramuscularly of the candidate vaccine at 21-day intervals. All the subjects included (n= 24,141) were adults; the average age was 29 years. The primary endpoint was the measure of vaccine efficacy in prevention of a symptomatic form of coronavirus disease occurring within 7 days after the second injection. Coronavirus infection was confirmed by a test PCR.
A vaccine effective against 5 variants!
A total of 165 people tested positive at the SARS-CoV-2. A portion (73.9%) of the samples could be sequenced. the variant Delta was responsible for 56 cases (45.9%), the Gamma variant for 53 cases (43.4%), the Alpha variant for 6 cases (4.9%), the Mu variant for 4 cases (3.3%) , and the Lambda variant of 3 cases (2.5%).
The efficacy of the vaccine was:
- 69.5% against symptomatic forms of the disease (all intensities combined);
- 78.8% against moderate to severe symptomatic forms of the disease.
Moreover, no serious cases occurred in the vaccinated group, while three serious cases were reported in the placebo group. The viral load was much lower in the vaccinated group. Regarding adverse effects, they were mild or moderate and transient. Although they were more frequent in the vaccinated group in the days following the injection compared with the placebo group (92.3% versus 45.5%), theimpact was similar in both groups 3 weeks after injection of each dose.
A study with some limitations
The authors regret not having been able to test the effectiveness of their vaccine candidate against the Omicron variant, which is now dominant on the planet but which was not yet in circulation at the time of the trial. This subject will be the subject of a subsequent publication.
This study has another limitation: very few patients over the age of 65 could be included in the trial, although it is in this age group that the virus done today the most victims.
This plant-based vaccine shows promise against Delta and Gamma variants of SARS-CoV-2
Article of Stephanie le Guillou published on February 15, 2022.
How to convince the most refractory to get vaccinated? By offering vaccines using technologies different frommessenger RNA. After the Novavax vaccine, the Canadian company Medicago unveils the promising results of its plant-based vaccine.
On February 14, 2022, nearly 53 million people had a complete vaccination schedule in France. The adoption of vaccination pass increased the numbers slightly. A glass ceiling seems to have been reached. So how do you convince the most refractory to get vaccinated? There are several reasons to delay the vaccine. Among them, rejection of vaccines based on messenger RNA technology comes first. The Novavax vaccine, soon to be available in France and based on more traditional technologies, may make it possible to increase vaccination coverage. More interestingly, in Canada, the results of a plant-based vaccine candidate have just been published.
The vaccine effectively prevents moderate to severe forms
This is a phase III, randomized, double-blind, placebo-controlled trial that was conducted in Argentina, Brazil, Canada, Mexico, Great Britain and the United States. The vaccination schedule included two intramuscular injections, 21 days apart. The primary endpoint was the prevention of symptoms of one SARS-CoV-2 infection. The samples could be sequenced. Contaminated persons were mostly infected with the Delta variant (n=45.9%) or the Gamma variant (n=43.4%).
A total of 24,141 people were included in the trial. Among them, 157 people were infected, 118 of whom were in the control group and 39 in the vaccinated group. The vaccine is therefore 71% effective in preventing symptomatic forms of Covid-19. Concerning the moderate to severe forms of the disease, 32 occurred in the control group against 8 in the vaccinated group. The efficacy against moderate to severe forms of the disease is 84.5% (excluding people who were positive at the start of the trial). Adverse effects were very rare and not serious.
How it works ?
The plant used is a cousin of tobacco, considered a weed. It has an excellent yield of protein production. The principle is the following. A bacterial vector, non-toxic for the plant, was injected with a plasmid containing the embarrassed who codes for the protein Spike of virus. The plant is then brought into contact with these bacteria : the cellular machinery of the plant will produce the Spike protein then expel it. All that remains is to retrieve it.
The file was submitted to Health Canada at the end of 2021 and could be approved in the coming weeks. In addition, this technology, which combines the traditional technique of viral particles and an innovative technique for producing them in a plant, can be transposed to other diseases.
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