May 20, 2020
Thom Carroll/for PhillyVoice
Thomas Jefferson University's Vaccine Center is developing a COVID-19 vaccine candidate that uses the existing rabies vaccine as a carrier for the SARS-CoV-2 antigen.
Thomas Jefferson University scientists have teamed up with Bharat Biotech, an Indian vaccine manufacturer, to continue the development of a COVID-19 vaccine that will use a rabies vaccine as a carrier, officials confirmed Wednesday.
The Jefferson Vaccine Center in Philadelphia first announced the COVID-19-rabies vaccine last month, calling it a safe and scaleable model that can address the unprecedented global reach of the coronavirus pandemic.
Approximately 90 vaccines for COVID-19 currently are in development. About 25% of them use an established vaccine carrier for the antigen of the coronavirus.
Instead of using the entire SARS-CoV-2 virus, the Jefferson team has embedded its characteristic spike protein within a killed rabies vaccine to induce antibody responses against both diseases.
"We are leveraging the properties of a very effective vaccine – one that provides lifelong immunity against one of the biggest global threats of our time,” said Dr. Mark Tykocinski, dean of Jefferson's Sidney Kimmel Medical College. “Rather than go with an untested approach, we have a leg-up by using a vaccine that is safe, effective and exceptionally good at creating a strong immune response – which is something not every vaccine can do.”
Bharat Biotech, located in Hyderabad in southern India, will facilitate end-to-end development of the vaccine, from clinical trials to commercial licensure, per its agreement with Jefferson.
The company also receives exclusive rights to develop, market and deliver the vaccine across the world, with the exception of the United States, Europe, Japan and other countries where Jefferson continues to seek partners.
“Our partnership with Bharat Biotech will accelerate our vaccine candidate through the next phases of development,” Jefferson Vaccine Center Director Matthias Schnell said. “We will be able to complete animal testing and move to phase 1 clinical trial rapidly."
An infectious diseases expert, Schnell led the development of previous rabies vaccines that were proven safe and effective in animal models when used as carriers in response to the 2003 SARS and 2012 MERS epidemics.
Preliminary tests of the new vaccine in animal models have shown a strong antibody response in mice. Results on whether vaccinated animals are protected from SARS-CoV-2 are expected in the next month.
One of the advantages of the Jefferson vaccine candidate is that the rabies vaccine has been proven safe for all populations, including children. The rabies vaccine also can be produced in a shelf-stable, dehydrated form — making it easy to reconstitute in any location.
"Bharat Biotech is committed to global public health and will be involved in an end-to-end development of the vaccine including comprehensive clinical trials to achieve commercial licensure," said CEO Dr. Krishna Mohan, who noted that the current goal is to begin initial human clinical trials by December.
Earlier this week, Moderna created waves when it announced "positive" data from early human clinical trials of its COVID-19 vaccine. Some scientists have expressed skepticism about whether the neutralizing antibodies presented in these results are durable, arguing Moderna must disclose more data to support its claims.
The Jefferson Vaccine Center hopes its vaccine candidate will benefit from the relatively low cost and global production capacity of existing rabies vaccines. Bharat Biotech is the world's largest supplier of rabies vaccines.
Schnell believes the strong immune response induced by the rabies vaccine will increase the chances of developing strong protection against SARS-CoV-2.
"Since we know the immune system reacts to the rabies vaccine with a strong response when we add the coronavirus component, we expect to see that level of protection, and immune memory, carry over to the SARS-CoV-2 viral protein as well," Schnell said.
