According to the research paper carried by bioRxiv, the preprint server for biology, the study has dispelled the uncertainty of possible neutralization escape.
A group of researchers from Indian Council of Medical Research(ICMR), National Institute of Virology, Pune and Bharat Biotech performed the plaque reduction neutralization test (PRNT50) using sera collected from the 26 recipients of BBV152/Covaxin against hCoV-19/India/20203522 (UK-variant) and hCoV27 19/India/2020Q111 (heterologous strain).
"A comparable neutralization activity of sera of the vaccinated individuals showed against UK-variant and the heterologous strain with similar efficiency, dispel the uncertainty of possible neutralization escape," says the paper, yet to be certified by peer review.
It noted the rapid surge inSARS-CoV-2 cases due to UK variant raised concerns in several countries. Many of these countries had direct flights to and from UK and the variant was associated with high transmissibility. Identification of other variants from South Africa also initiated a global discussion on the challenges that these new variants could pose to the current vaccine candidates.
The genome of the UK-variant has 17 mutations, eight of which were found in spike receptor-binding domain (RBD) mediating the attachment of the virus to the angiotensin converting enzyme 2 (ACE2) receptor on the surface of human cells. Therefore, it appeared that the majority of the vaccine candidates, being either recombinant or specifically targeting the single epitope of original D614G ancestral spike sequence, might not be able to generate an efficient immune response against the new variants.
"Here, we successfully isolated and characterized the hCoV-19/India/20203522 SARS-CoV-2 (VOC) 202012/01 from UK returnees in India with all signature mutations of the UK-variant," it added.
The new finding has come close on the heels of prestigious medical journal The Lancet Infectious Disease publishing phase-1 clinical trials studies of Covaxin.
According to the journal, the vaccine produced tolerable safety outcomes and enhanced immune responses in its phase 1 trials.
Bharat Biotech said this is the first clinical trial publication on a Covid-19 vaccine from India.
The developments came amid controversy over efficacy of Covaxin, whose phase 3 trials are still underway.
Covaxin is being administered in India in clinical trial mode as part of the nation-wide vaccination programme launched for healthcare workers on January 16.
The vaccine maker on January 22 announced that 13,000 volunteers have been successfully administered the second dose of Covaxin in the phase-3 trials.
The phase-3 human clinical trials of Covaxin began mid-November, targeted to be done in 26,000 volunteers across India.
Covaxin is a highly purified and inactivated 2 dose SARS-CoV2 vaccine, manufactured in a Vero cell manufacturing platform with an excellent safety track record of more than 300 million doses.
India's first indigenous Covid-19 vaccine by Bharat Biotech is developed in collaboration with ICMR - NIV.