HYDERABAD: Vaccine maker Bharat Biotech has joined hands with US-based ViroVax LLC for using the latter’s adjuvant Alhydroxiquim-II to boost immune response and longer lasting immunity of its indigenous, inactivated Covid-19 vaccine candidate Covaxin, which is currently undergoing Phase II clinical trials.
Bharat Biotech has entered into a licencing agreement with the Kansas-based ViroVax for using its technology and has been using the adjuvant since the development of the vaccine began.
The SARS-CoV-2 virus strain that is being used for the development of Covaxin was isolated at the National Institute of Virology (NIV), Pune, and the inactivated virus was formulated with ViroVax’s adjuvant to produce the vaccine candidate.
Bharat Biotech chairman and managing director Dr Krishna Ella said the tie-up with ViroVax is part of Bharat Biotech’s efforts to develop safe and effective vaccines that offer long term immunity.
“There is a critical need for development and availability of adjuvants that elucidate mechanisms of action inducing greater anti-body responses to vaccine antigens, resulting in long-term protection against pathogens. Adjuvants also enhance the sustainability of the global vaccine supply because of their antigen-sparing effect,” he explained.
According to Ella, Aluminium hydroxide, which is the widely used adjuvant in the development of SARS CoV-2 vaccines, is known to induce a Th2 based response, which is important for eradication of extracellular parasites and bacterial infection but 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 aluminum hydroxide gel) as an adjuvant,” he explained.