Covaxin effectively neutralises Delta variant of COVID: NIH
Covaxin comprises an inactivated SARS-CoV-2 virus that cannot replicate but still stimulates the immune system to make antibodies against the virus.
India’s Covaxin effectively neutralises both Alpha and Delta variants of coronavirus, said the US’ National Institute of Health (NIH). The COVID-19 vaccine has been developed by Bharat Biotech in collaboration with the Indian Council of Medical Research.
The NIH said that the results of two studies of blood serum that was taken from people who had received Covaxin suggest that the vaccine generates antibodies that effectively neutralise the B.1.1.7 (Alpha) and B.1.617 (Delta) variants of SARS-CoV-2. The Alpha and Delta variants were first identified in the UK and India respectively.
NIH further stated that an adjuvant developed with funding from it has contributed to the success of the highly efficacious Covaxin, which has been administered to roughly 25 million people in India and elsewhere.
What is an adjuvant?
Adjuvants are substances that are formulated as part of a vaccine to boost immune responses and enhance a vaccine’s effectiveness.
Which adjuvant was used in Covaxin?
• Alhydroxiquim-II was the adjuvant that was used in Covaxin. The adjuvant was discovered and tested in a laboratory by the biotech company ViroVax LLC of Lawrence, Kansas with support from the NIAID Adjuvant Development Program.
• It is the first adjuvant in an authorised vaccine against infectious disease to activate receptors TLR7 and TLR8 that play a vital role in the immune response to viruses.
• The alum in Alhydroxiquim-II also stimulates the immune system to search for an invading pathogen.
• Molecules that activate TLR receptors stimulate the immune system powerfully, but the side effects of Alhydroxiquim-II are mild.
Anthony S Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID), part of NIH said, “I am pleased that a novel vaccine adjuvant developed in the US with NIAID support is part of an efficacious COVID-19 vaccine available to people in India."
Bharat Biotech, NIAID collaboration
• Bharat Biotech signed a licensing agreement with Sunil David, founder and chief executive officer of ViroVax, to use Alhydroxiquim-II in their candidate vaccines.
• The collaboration between Dr David and Bharat Biotech was first initiated during a 2019 meeting in India, which was coordinated by the NIAID Office of Global Research under the auspices of NIAID’s Indo-US Vaccine Action Program.
• Then a delegation of five NIAID-funded adjuvant investigators, including Dr David and two members of the NIAID Division of Allergy, Immunology and Transplantation and the NIAID India representative had visited four leading biotechnology companies here to learn about their work and discuss potential collaborations.
• The delegation also attended a consultation in New Delhi, hosted by India’s National Institute of Immunology and co-organised by NIAID and India’s Department of Biotechnology.
• The agreement to use Alhydroxiquim-II in their candidate vaccines was among the many scientific collaborations sparked by these activities.
• During the outbreak of the COVID-19 pandemic, the license agreement was expanded to use Alhydroxiquim-II in Covaxin, which had received Emergency Use Authorisation in India and over a dozen other countries.
• The company conducted extensive safety studies of Alhydroxiquim-II and undertook the process of scaling up production of the adjuvant under Good Manufacturing Practice standards.
• Bharat Biotech expects to produce an estimated 700 million doses of Covaxin by the end of 2021.
Covaxin trial results
• Covaxin comprises an inactivated SARS-CoV-2 virus that cannot replicate but still stimulates the immune system to make antibodies against the virus.
• The published Phase 2 trial results of the vaccine indicate that it is safe and well-tolerated.
• The safety and efficacy data from the vaccine's Phase 3 clinical trials will become available later this year.
• According to NIH, the unpublished interim results of the phase 3 trial indicate that the vaccine has 78 percent efficacy against symptomatic disease and 100 percent efficacy against severe COVID-19 including hospitalisation and 70 percent efficacy against asymptomatic infection with SARS-CoV-2.
Dr. Sunil David, M.D., Ph.D. had been working since 2009 to search for novel molecules that activate innate immune receptors and developing them as vaccine adjuvants. The NIAID Adjuvant Program has supported his research.