Corbevax, a protein sub-unit COVID-19 vaccine, manufactured by Hyderabad based Biological E and developed by scientists at the Baylor College of Medicine, Houston is the first patent free COVID-19 vaccine. This allows the technology to be replicated across the world for which Baylor college of medicine will receive a small free. This step will include a technology transfer and also reduce the costs of production of the vaccine.
Furthermore, the vaccine uses an already established technology platform to release the protein sub-unit. The SARS-CoV-2 protein is released by a yeast which is how Hepatitis B vaccines are created as well. While Hep B vaccines use the yeast Saccharomyces cerevisiae as the host and medium for recombination, the COVID-19 vaccine uses another yeast called Pichia pastoris wherein the spike protein will replicate.
The vaccine received emergency use authorisation in India on December 28, 2021 along with Covovax produced by Novovax and Serum Institute of India. However, it is unclear as to when the vaccine will be introduced into the vaccination program as India intends to continue providing Covishield and Covaxin as precautionary booster doses to the eligible population.
The government of India has placed an order of 300 million doses of this vaccine. The scientists Peter Hotez and Maria Bottezi who developed the vaccine believe that this vaccine could act as perfect booster dose vaccine to curb the spread of the ongoing Omicron variant. Indian authorities are still vouching for homologous booster shots which means that health workers and those above 60 can only take Covishield or Covaxin as a precautionary dose depending on which vaccine was administered to them earlier. Although health officials have spoken about mixing vaccines, India has not yet decided to go ahead with the same.
How Is The Vaccine Unique?
All the other available viruses are either using mRNA technology, inactivating the live virus, or using other viral vectors to create COVID-19 vaccines. Corbevax and Covovax use recombinant protein technology for creating the vaccines which is an established technology and platform to create vaccines against major diseases.
In case of Corbevax, after the SARS-CoV-2 genome was made public in January and February 2020, scientists at Baylor College of Medicine chose to isolate the virus and separate the spike protein from the other proteins and replicating genome of the virus. The spike protein is the unit which assists SARS-CoV-2 and its many variants to bind faster to cells in the human body and makes it easier for the virus to enter the cells, proliferate, and replicate.
Dr.Hotez and Dr. Bottezi and their team, then inserted the spike protein into the yeast thus allowing recombination. Recombinant proteins are those where specific proteins are allowed to replicate without the help of an original replicating RNA or DNA and allowed to express their role on their own. In this case, the spike protein was produced without any infectious components of the existing virus.
Yeasts are used as the host as they grow rapidly and are easy to manipulate genetically. They also secrete the proteins outside their cell body thus allowing them to be used to create vaccines. The spike protein after replication was cleaned to remove all the remnants of the yeast and then later used with adjuvants like aluminium hydroxide gel and CpG 108 to enhance the expression of the vaccine. These adjuvants do not mix with the contents of the vaccine and act only as catalysts.
The vaccine can then be administered. India's drug general and the Central Drugs Standard Control Organisation gave emergency use authorisation to the drug after its clinical trials showed positive results. The efficacy of the vaccine is estimated to be 90 per cent but the results have not yet been published in any peer-reviewed journal.
Patent Free And Equitable
The vaccine developers have decided to not apply any patents on the technology of the vaccine due to which it will be easier to replicate across the world. The makers want to ensure that the vaccine is made available to as many people and protect them from contracting severe disease.
Along with being patent free, the medium yeast that the vaccine uses to grow the Spike protein is also cheap and easily available. This reduces the cost of making the vaccine. Recombinant protein technology has been a part of vaccine technology since the 1980s and is also used to make the Hepatitis B vaccine.
As the cost of production is going to be lower, it is estimated that the vaccine could be available for ₹250 for one dose and about ₹400. Although India has purchased close to 300 million doses, there are no news on when the vaccine will be made available.
According to the developers, Biological E has already manufactured close to 100 million doses and has the capability to manufacture the same in the upcoming year.