Coronavirus vaccine Covaxin will use adjuvant Alhydroxiquim-II to boost immune response and longer lasting immunity.
The technology is being used under a licensing agreement with Kansas-based ViroVax, said Bharat Biotech, which is currently conducting phase II human trials of Covaxin.
“Our partnership with ViroVax resonates with Bharat Biotech’s relentless efforts towards developing safe and effective vaccines coupled with long term immunity,” the Hyderabad-based vaccine maker’s CMD Krishna Ella said.
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In a statement, announcing the licensing agreement, he said there is critical need for development and availability of adjuvants that elucidate mechanisms of action inducing greater antibody responses to vaccine antigens, thus resulting in long-term protection against pathogens. Adjuvants also enhance the sustainability of the global vaccine supply on account of their antigen-sparing effect.
Covaxin is an inactivated vaccine derived from a strain of SARS-CoV-2 virus isolated at the National Institute of Virology (NIV), Pune. The inactivated virus is formulated with ViroVax’s adjuvant to produce the vaccine candidate, the release said.
Mr. Ella said the widely used adjuvant Aluminium hydroxide in the development of SARS CoV-2 vaccines is known to induce a Th2 based response (which are important for eradication of extracellular parasites and bacterial infection). The Th2 based response has a theoretical risk of vaccine associated enhanced respiratory diseases (VAERD or ADE). “We have used Imidazoquinoline class of adjuvants (TLR7/8 agonists), which are known to induce Th1 based response which further reduces the risk of ADE (Anti-Body Dependent Enhancement).
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“In our preclinical studies and animal challenge models (Syrian Hamster and Rhesus Macaques) we have shown that Covaxin induced Th1 based response due to the use of Algel-IMDG (chemosorbed imidazoquinoline onto the aluminum hydroxide gel) as an adjuvant,” he said.
Sunil David of ViroVax said the firm is delighted to partner with Bharat Biotech. “This has been possible because of support from the National Institutes of Health,” he said.
ViroVax also received supplemental funding for development of subunit vaccine constructs for the prevention of COVID-19 and for the discovery and development of therapeutics for treating COVID-19. ViroVax is evaluating a subunit vaccine candidate and has identified potential antiviral therapeutics. It is currently in the process of testing the efficacy of these compounds, the release said.