Vaccine maker Bharat Biotech has revealed the use of an adjuvant with its Covid-19 vaccine to boost the immune response and provide longer-lasting immunity.
The adjuvant Alhydroxiquim-II is being used under a licensing agreement with Kansas-based ViroVax LLC. An adjuvant is a pharmacological ingredient added to enhance a vaccine’s immune response.
Covaxin, India’s first indigenously developed vaccine candidate for Covid-19 is presently undergoing Phase-II human trials across the country.
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 widely used adjuvant Aluminium hydroxide in the development of SARS CoV-2 vaccines is known to induce a Th2 based response which is important for the eradication of extracellular parasites and bacterial infection,” Dr Krishna Ella, chairman and managing director, Bharat Biotech said.
“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)” Dr Ella said.
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 aluminium hydroxide gel) as an adjuvant, Dr Ella adds.
According to a press statement from Bharat Biotech, ViroVax received supplemental funding for the development of sub-unit vaccine constructs for the prevention of Covid19, and for the discovery and development of therapeutics for treating Covid-19. ViroVax is evaluating a sub-unit vaccine candidate and has identified potential antiviral therapeutics. It is currently in the process of testing the efficacy of these compounds.
Dr Ella further states that “there is a 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.”
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