The worldwide increase in circulation of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has led to the crossing of shocking milestones in 100 million reported cases. Among the main causes of the increase in infections is the emergence of new mutants, especially those in the United Kingdom, that are more infectious compared to their ancestral strains.However, a new preprint research treatise submitted to the preprint server bioRxiv* Shows data showing that Indian-made Covaxin vaccine candidates successfully neutralize this mutant and prevent infection when attacked.
The British variant, also known as Variant of Concern (VOC) 202012/01, is also known as strain B.1.1.7 or 20B / 501Y.V1. The proportion of new cases of COVID-19 in the UK is increasing rapidly in less than two months. B.1.1.7 has also been sequenced from other countries, with direct flights connecting many such affected regions to the United Kingdom, resulting in a dramatic increase in cases worldwide. The possibility of doing so is clear.
Similar concerns have been expressed for the so-called South African variants, highlighting the issues raised by these variants regarding the protection of the newly available COVID-19 vaccine.
The UK variant has 17 mutations in the genome and 8 in the spike receptor binding domain (RBD). This allows the virus to attach to the angiotensin converting enzyme 2 (ACE2) receptor in the target host cell.
The UK has begun vaccination with the Pfizer-BioNTech vaccine and the Oxford-AstraZeneca vaccine. Both are mRNA vaccines and induce spike antigen expression in the early SARS-CoV-2 strain. The multi-million dollar question is whether many of the spike mutations found in later variants affect the ability of vaccine-induced antibodies directed against the previous D614G spike version to neutralize the virus.
Covacin is a unique inactivated total virion SARS-CoV-2 vaccine BBV152. High neutralization efficacy in Phase I clinical trials against allogeneic hCoV-19 / India / 2020770 strains and two other heterologous unclassified cluster strains, hCoV-19 / India / 2020Q111 and hCoV-19 / India Has been reported. / 2020 Q100. In particular, all three strains carry the N501Y mutation characteristic of the UK strain Spike RBD.
Phase II trials showed impressive results in the plaque reduction neutralization study (PRNT50), where immune sera from covacin recipients have the ability to reduce viral infection levels in cultured cells with low post-immunization titers. Was shown. Seroconversion and neutralizing antibody production occurred in 99.6% of subjects.
(A) Neutralizing antibody response to BBV152 / COVAX INTM vaccinated serum against SARS CoV-2 strain: Neutralizing antibody to vaccine serum against hCoV-19 / India / 2020770 (homologous), hCoV-19 / India / 20203522 (heterologous UK) Potency (PRNT50) strain) and hCoV-19 / India / 2020Q111 (heterogeneous unclassified cluster). The bars represent the geometric mean and standard deviation of each group titer. The nonparametric Kruskal-Wallis test was used to compare PRNT50 values in different groups. P values above 0 • 05 are considered insignificant and are marked in the figure (ns-not significant). (B) Comparison of serum PRNT50 values of each vaccine recipient with three strains of SARS CoV-2: hCoV-19 / India / 2020770 (homologous), hCoV-19 / India / of each vaccinated person’s serum Neutralizing antibody titers (PRNT50) 20203522 (heterologous UK strain) and hCoV-19 / India / 2020Q111 (heterologous unclassified cluster) bars represent the mean and standard deviation of each serum.
Studies show efficacy against British variants
The current study reports the results of a neutralization study of serum samples from Phase II study participants for the UK variant.
Researchers first isolated and sequenced British variants from Indian returnees to the United Kingdom. Isolate hCoV-19 / India / 20203522 showed all the characteristic mutations found in SARS-CoV-2 (VOC) 202012/01.
Serum from 38 BBV152-immunized subjects was tested against British variants. At the same time, sera from 20 subjects were tested against one of the above heterologous unclassified strains, hCoV-19 / India / 2020Q111.
The PRNT50 test showed that the median neutralization was 0.8 and 0.9. Effectiveness When the allogeneic strain hCoV-19 / India / 2020770 is compared with the UK mutant hCoV19 / India / 20203522 and other heterologous strains hCoV-19 / India / 2020Q111, respectively.
In other words, Neutralizing antibody Immunization-induced immunization with BBV152 / Covaxin is equally effective against both the locally circulating homologous strain hCoV-19 / India / 2020770 and the UK mutant hCoV-19 / India / 20203522. did. It also proved to be effective in neutralizing another heterologous strain hCoV-19 / India / 2020Q111.
What is the impact?
Previous studies have shown that British variants have avoided neutralization Convalescent plasma Contains high titer neutralizing antibodies. This was demonstrated to be due to the presence of the E484 substitution associated with the subsequent insertion of 11 amino acids into the NTDN5 loop of the spike antigen.
This has led to a lot of uncertainty as to whether current vaccines will neutralize new mutants. Current studies alleviate such concerns by demonstrating highly comparable neutralizing activity in vaccinated individuals against allogeneic and heterologous strains of the virus. These results indicate that mutations in UK mutants do not mediate immune evasion to neutralizing antibodies induced by covaxin vaccination.
Covaxin is being deployed in the world’s largest vaccination program in India, along with the Oxford Astra-Zeneca vaccine made in India, which is distributed under the name Covishield. “It is unlikely that mutation 501Y can undermine the potential benefits of the vaccine,” the researchers said.
bioRxiv Publish preliminary scientific reports that should not be considered definitive as they are not peer-reviewed, guide clinical / health-related behaviors, and should not be treated as established information.
Indian covaxin vaccine likely to be effective against SARS-CoV-2 mutants in the United Kingdom: Study
Source link Indian covaxin vaccine likely to be effective against SARS-CoV-2 mutants in the United Kingdom: Study
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