Australian Researchers Repurposed Old Vaccine to Protect Against COVID-19
Researchers at the University of Sydney and Centenary Institute announced they are repurposing the old tuberculosis vaccine to see if it can be used as a preventive vaccine against the SARS-CoV-2 virus.
The vaccine candidate, which Australian researchers have called BCG:CoVac, combines the vaccine for tuberculosis, Bacille Calmette-Guérin (BCG) with major components of the SARS-CoV-2 virus.
In BCG:CoVac, the BCG vaccine is used as a vehicle to deliver distinctive proteins that originate from the SARS-CoV-2 virus surface.
The goal is for the human immune system to develop a memory of SARS-CoV-2 and develop immunity. The SARS-CoV-2 virus is the pathogen that causes COVID-19 disease in humans.
The study’s lead investigator Professor Jamie Triccas, from the School of Medical Sciences, Faculty of Medicine and Health, and the Charles Perkins Centre said in a press statement published on July 3, 2020, ‘the team was motivated to apply their expertise in studying vaccines to assess the effectiveness of this new formulation.’
“We have over 2 decades of experience in the development and testing of tuberculosis vaccines, which will be applied for the assessment of BCG:CoVac”.
“There have yet to be studies published that combine BCG and components of the SARS-CoV-2 virus as part of new vaccine design, and we’re excited to test their potential,” said Professor Triccas.
The researchers’ early unpublished results from pre-clinical testing in mice show BCG:CoVac stimulated an immune response aimed to control virus infection in humans.
In mice vaccinated with BCG:CoVac, the vaccine-induced high levels of SARS-CoV-2-specific antibodies. The role of these antibodies is to bind the virus and help eliminate it from the body.
The vaccine also triggered a strong anti-viral response by T cells, which is a type of immune cell.
Both these types of immune responses are thought to be important to ensure clearance of the SARS-CoV-2 virus from infected individuals, stated these researchers.
Additionally, preliminary data also showed BCG:CoVac did not create high levels of inflammatory responses, which is a common barrier and concern in vaccine design.
“These initial results are very promising. BCG:CoVac is making the type of immune response that we predict is needed to control SARS-CoV-2 infection in humans,” said Professor Triccas.
“We are currently determining how well the antibodies generated after vaccination can ‘block’ the virus from infecting cells and thus provide protection from disease”.
There is currently a global interest in the BCG vaccine, which is being investigated in ongoing clinical trials as a possible intervention to protect vulnerable people during the COVID-19 pandemic.
This is because of suggestions the BCG vaccine has other beneficial effects on the immune system that could protect against other infections.
A 2019 observational study reported the vaccine is related to fewer deaths from certain infections other than from TB in low-income countries.
However, current COVID-19 related studies only investigate the protective effects of the BCG vaccine by itself.
Dr. Claudio Counoupas, a research scientist at the Centenary Institute and co-lead on the project, said: “This provides a specific ‘memory’ immune response against the virus that could provide long-term protection against disease.”
“Our on-going studies will determine how long the immune response lasts after vaccination in animal models. This is important information for future human testing of our vaccine.”
Declaration: The researchers declare no competing interests. Ethics approval was obtained from the Sydney Local Health District Animal Welfare Committee and the study strictly adhered to all relevant guidelines and legislation.
Coronavirus vaccine development news is published by Precision Vaccinations.