New type of Covid-19 protein subunit vaccine have been developed by the pharmaceutical companies like Novavax, Medicago and Sanofi.
A new kind of Covid-19 vaccine—that works somewhat differently from the current crop of jabs approved for use in the United States and other countries—could be available soon.
The protein subunit vaccine is based on a well-understood technology, and it doesn’t need a special refrigerator for storage.
The American company Novavax has developed a Covid-19 protein subunit vaccine candidate—which contains specific isolated proteins from viral or bacterial pathogens.
The results of a massive test of the Novavax Covid-19 vaccine’s efficacy in tens of thousands of volunteers in the United States and Mexico are nearing completion.
Dr Gregory Glenn, president of research and development for Novavax, told during a recent webinar presented by the International Society for Vaccines: “We anticipate filing for authorisation in the U.K., U.S. and Europe in the third quarter”.
Novavax uses enormous vats of cells produced in the lab to generate the virus protein.
However, there is another way to create the protein—grow it in a greenhouse. This is what the Canadian biotech firm Medicago have done to develop its protein subunit vaccine.
The plants utilised are linked to tobacco plants and have been genetically engineered to include the viral protein instructions.
These plants form a lipid shell around a group of viral proteins, with the proteins protruding.
Nathalie Landry, Medicago’s executive vice president for scientific and medical affairs, explained that the plant will build the protein in a way that resembles the virus’s structure and appearance.
“So, if you look at an image of it, it looks like a virus, but it cannot induce any disease. But when [it’s] injected as a vaccine your body will raise a good immune response,” she added.
Early investigations suggest that Medicago’s candidate vaccine does just that, and the company is so confident in its findings that it has already started massive human research that could involve up to 30,000 volunteers across 11 nations.
There is another protein subunit vaccine candidate from French pharmaceutical giant Sanofi.
In 2020, Sanofi was preparing to launch a comprehensive trial of the vaccine’s effectiveness when preliminary findings in a smaller group of participants revealed that it did not appear to be eliciting the protective immune response.
Dr Paul Goepfert, an expert from the University of Alabama at Birmingham and was one of the researchers involved in those early studies said: “Especially in elderly individuals in that study, it was not as immunogenic as it should be”.
According to him, the problem was caused by an error in the vaccine dose calculation.
As a result, instead of administering 10 micrograms of the dose, they only gave one microgram, said the expert.
Sanofi has fixed the issue, and now the company is enrolling volunteers in a large efficacy trial.
Meanwhile, the Indian government has placed an order of 30 crore doses of the Corbevax vaccine.
Corbevax, a recombinant protein subunit, was developed by the Texas Children’s Hospital Center for Vaccine Development at Baylor College of Medicine, and in India, it is being manufactured by Hyderabad-based Biological E.
This two-dose vaccine is now in phase 3 trial after the phase 1 and 2 trials showed promising results.