By Erum Salam

A new Covid-19 vaccine is being developed by Texas scientists using a decades-old conventional method that will make the production and distribution cheaper and more accessible for countries most affected by the pandemic and where new variants are likely to originate due to low inoculation rates.

The team, led by Drs Peter Hotez and Maria Bottazzi from the Texas Children’s Hospital Center for Vaccine Development at Baylor College of Medicine, has been developing vaccine prototypes for Sars and Mers since 2011, which they reconstructed to create the new Covid vaccine, dubbed Corbevax, or “the world’s Covid-19 vaccine”.

Although more than 60 other vaccines are in development using the same technology, Bottazzi said their vaccine is unique because they do not intend to patent it, allowing anyone with the capacity to reproduce it.

“Pretty much anybody that can make hepatitis B vaccines or has the capacity to produce microbial-based protein like bacteria or yeast, can replicate what we do,” Bottazzi said.

Patent wars over mRNA vaccines have recently heated up. Moderna and the National Institutes of Health are in a dispute over who should get credit for specific discoveries that led to a Covid-19 vaccine which has been delivered to more than 73 million Americans. If Moderna is found to have infringed on the federal government’s patent, it could be forced to pay more than $1bn.

At the same time, activists have called for Pfizer and Moderna to share the technology and knowhow for producing their vaccines, including taking the fight to the World Trade Organization. Low-income countries, which have few vaccine research and production facilities, have vaccinated just one in nine people, according to the World Health Organization. The US has fully vaccinated 67% of the population and provided a third vaccine dose to more than one-third.

Corbevax’s clinical trial data has yet to be released due to resource constraints, but Texas Children’s hospital said the vaccine was over 90% effective against the original Covid-19 strain and over 80% effective against the Delta variant. The vaccine’s efficacy against the Omicron variant is currently being tested.

The process to create the vaccine involves the use of yeast – the same method by which hepatitis B vaccines are produced.

The Moderna, Pfizer and Johnson & Johnson vaccines currently authorized in the US use different technologies, or vaccine “platforms”. Moderna and Pfizer use messenger RNA (mRNA) technology. This platform introduces the immune system to Covid-19 by delivering instructions on how to produce its most recognizable feature, the spike proteins which coat its surface. This helps the immune system recognize and fight the virus later, if a person is exposed. Johnson & Johnson’s vaccine introduces immune cells to the spike protein through an otherwise harmless cold virus, a technology called viral vector.

The Corbevax vaccine uses a platform called recombinant protein sub-unit technology, which places an actual piece of Covid-19’s spike protein in yeast cells. The yeast cells then copy the vital protein and the protein is introduced to the immune system.

“We make the protein, directly and synthetically, in the lab using the yeast system,” Bottazzi explained. “We ask the yeast to make a protein that looks just like a protein that is made by the virus. Then we immunize the protein and the body then processes this protein and presents it to the immune system. Therefore, you don’t ask your body to do any major manipulation of the coding.”

Crucially, storing the Corbevax vaccine only requires standard refrigeration, unlike the Pfizer vaccine, which requires ultra-cold storage in transit.

Biological E, an Indian pharmaceutical company accustomed to producing hepatitis B vaccines with whom Bottazzi’s team has a longstanding relationship, has already produced 150m doses of the new Corbevax vaccine and will soon be able to produce 100m doses every month.

After being overlooked by government organizations for funding, Bottazzi said, the developers behind Corbevax relied on philanthropic donations to get them over the finish line. The Texas Children’s Hospital Center for Vaccine Development is an academic and scientific institution in nature, but Bottazzi said developing Corbevax had forced them to stretch their resources in order to gain visibility as a serious candidate for Covid vaccine development.

“We ourselves are learning how to do work that is regulatory-enabling, that enables good quality, good reproduction, good record-keeping … we mimic as if we were a small biotech or manufacturing entity,” she said. “Every technology has pros and cons. Nobody is claiming one is the super-duper, only solution. All the [vaccines] are part of the solution. But when you have a situation of such gravity around the world, you don’t pick and choose a solution – you try to use all solutions,” Bottazzi said.

Bottazzi said the reason she and her team did not patent the vaccine was because of her team’s shared philosophy of humanitarianism and to engage in collaboration with the wider scientific community.

“We want to do good in the world. This was the right thing to do and this is what we morally had to do. We didn’t even blink. We didn’t think, ‘how can we take advantage of this?’ You see now that if more like us would have been more attuned to how the world is so inequitable and how we could have helped from the beginning so many places around the world without thinking ‘what’s going to be in it for me?’, we could have basically not even seen these variants arise.”

Bottazzi hopes her move will incentivize others to follow suit and make affordable and accessible vaccines for other diseases and viruses, like hookworm.

“We need to break these paradigms that it’s only driven by economic impact factors or return of economic investment. We have to look at the return in public health.”

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