Bharat Biotech’s Covaxin may effectively neutralise both Alpha and Delta variants of coronavirus, finds the US National Institute of Health study.
The study findings showed that blood serum from people who had received Covaxin suggested that the vaccine generates antibodies that effectively neutralise the B.1.1.7 (Alpha) and B.1.617 (Delta) variants of SARS-CoV-2, first identified in the UK and India, respectively.
Covaxin comprises an inactive form of SARS-CoV-2 that cannot replicate but still stimulates the immune system to make antibodies against the virus. The adjuvant used in Covaxin, Alhydroxiquim-II, was discovered and tested in a laboratory by the biotech company ViroVax LLC of Lawrence, Kansas with support from the HIH’s NIAID Adjuvant Development Program.
Alhydroxiquim-II is the first adjuvant in an authorised vaccine against an infectious disease to activate receptors TLR7 and TLR8 that play a vital role in the immune response to viruses. In addition, the alum in Alhydroxiquim-II 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, the NIH said.
Published results from a phase 2 trial of the vaccine indicate that it is safe and well tolerated, the NIH said, adding that safety data from a phase 3 trial of Covaxin will become available later this year.
“Meanwhile, unpublished interim results from the phase 3 trial indicate that the vaccine has 78 per cent efficacy against symptomatic disease, 100 per cent efficacy against severe COVID-19, including hospitalisation, and 70 per cent efficacy against asymptomatic infection with SARS-CoV-2, the virus that causes COVID-19, it said.