The researchers took the gene that codes for the spike protein and engineered yeast to produce it. These proteins are collected, purified, and combined with an adjuvant to enhance immune responses. This exact method has been used to produce the hepatitis B vaccine for years.
“Protein-based vaccines have been widely used to prevent many other diseases, have proven safety records, and use economies of scale to achieve low-cost scalability across the world,” says Maria Elena Bottazzi, one of the lead researchers on the project.
In late 2020 the US research team developing the vaccine joined forces with India-based pharma company Biological E to begin clinical trials and establish manufacturing capacity. Across 2021 those clinical trials included several thousand participants and ultimately found Corbevax to be safe and effective at generating robust immune responses to SARS-CoV-2.
The trial data was compared to an already approved vaccine called Covishield (the Indian-made version of Astrazeneca’s well-known COVID-19 vaccine). Corbevax generated significantly fewer adverse effects than Covishield and produced superior immune responses.
Neutralizing antibody responses to Corbevax indicate the vaccine should be at least 80 percent effective at preventing symptomatic COVID-19 from the Delta variant. Specific data against the Omicron variant is expected soon but it is hypothesized to be at least as effective as most currently available vaccines.
Perhaps the most important feature of this new vaccine is the fact it has been developed as a patent-free product that can be easily manufactured by vaccine-producers around the world. Peter Hotez, one of the researchers leading the project, has described it as a “gift to the world,” pointing out the technology has already been transferred to vaccine producers in India, Indonesia, Bangladesh and Botswana.
“This announcement is an important first step in vaccinating the world and halting the pandemic,” says Hotez. “Our vaccine technology offers a path to address an unfolding humanitarian crisis, namely the vulnerability the low- and middle-income countries face against the delta variant.”
The vaccine is similar to Novavax’s protein sub-unit COVID-19 vaccine, which was recently authorized for emergency use in a number of countries around the world. India is the first country to issue emergency authorization to Corbevax and Biological E reportedly has 150 million doses ready to go, with production capacity set for 100 million doses per month from February.
Source: Texas Children’s Hospital
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