Amidst concerns of a new Covid wave in India following massive surge in China and other countries, research at AIG Hospitals here has revealed that Corbevax booster in individuals vaccinated with Covishield gives maximum protection against Omicron variants.
The scientific study has proved the immunity benefits of the indigenous heterologous vaccine booster, Corbevax in combating Omicron variants.
The study titled "Heterologous booster dose with Corbevax following primary vaccination with Covishield enhances protection against SARS-CoV-2" has been published in the high-impact factor journal "Vaccines".
Announcing the findings of the study, AIG Hospitals Chairman Dr D Nageshwar Reddy told media persons that the study was done on 250 healthcare workers who had received 2 doses of Covishield as the primary vaccine regimen not more than 6 months ago. None of the participants had any adverse events following the administration of Corbevax booster dose.
"We knew from our previous studies that mixed vaccines produce better immune response; therefore, when the government approved Corbevax to be given as a heterologous booster to individuals already vaccinated with Covishield, our aim was to determine how a different vaccine platform (protein-based) will impact the immune response especially in context of the Omicron variant," he said.
Corbevax is an indigenously developed peptide-based vaccine that is different from the viral vector (Covishield) or the inactivated vaccine (Covaxin). The key difference is that Corbevax uses only a protein subunit of the virus replicated inside a yeast cell while the others are whole virus vaccines. The advantage of peptide-based vaccine is that it considerably reduces the risks of allergic and autoimmune responses making them safe for widespread usage.
Dr Reddy said the results further cemented their belief that mixed vaccines are absolutely safe. "The second aspect of the study was to measure the antibody response as well as the T-cell (memory cell) response at 30 days and then at 90 days to correctly estimate the overall protection against the circulating Omicron variant.
When estimating the effectiveness of a vaccine, both the antibody response and T-cell (Memory cell) response are essential.
"In our study, we compared the immune responses among those individuals who were given the same vaccine, i.e., Covishield (homologous group) as a booster and those who were given Corbevax as a booster (heterologous group). The S1/S2-spike protein IgG antibody levels and T/B Cell response of these groups were compared at 30 days and at 90 days. While the homologous and heterologous groups showed increased S1/S2-spike protein IgG antibody level at 30 days, the heterologous group (Corbevax as a booster) showed higher levels of antibodies at both 30 days and 90 days," Dr Reddy said.
The study was undertaken when Omicron variants are circulating in India; therefore, it would be appropriate to say that heterologous booster (Corbevax) would be effective in combating any wave that is fueled by sub-variants of the Omicron.
High-risk group people should consider taking the booster dose and continue to take Covid appropriate precautions all the time especially when in public spaces.
Replying to queries, Dr Reddy said if a person has taken Covaxin double dose, he should also take Corbevax as the booster dose. "The booster dose should be from the other company as this gives more protection," he said.
He noted that only 28 per cent of people in the country have taken booster dose. Corbevax is manufactured by Hyderabad-based Biological E.
Dr Reddy said that the vaccine is easy to manufacture and it is already available in the market at a price of Rs 250.
He suggested that China should also import Corbevax to save lives.
Dr Reddy also made it clear that there is no need for panic as the both the central and state governments are taking necessary measures and adequate stocks of vaccines and Remdesivir are available.
He believes that the number of Covid cases may increase over the next two months but from March next year, the situation will be normal.
He said people should wear masks while going in crowded places. He believes that the impact of the new variant of Omicron will not be severe.