First ever comparative study reveals that Covishield outperformed Covaxin
The study was carried out by a group of 11 institutes, led by scientists from the National Centre for Biological Sciences.
A first ever comparative study has revealed that Covishield outperformed Covaxin as vaccine during the Covid-19 pandemic. The study not only provides comparison data of both vaccines but also paves the way for establishment of technology required for immunology assessment in future.
The study titled, “Immunogenicity of SARS-CoV-2 vaccines BBV152 (COVAXIN) and ChAdOx1 nCoV-19 (COVISHIELD) in seronegative and seropositive individuals in India: a multicentre, non-randomized observational study” has been published in the journal, The Lancet Regional Health Southeast Asia on March 6. The study was carried out by a group of 11 institutes, led by scientists from the National Centre for Biological Sciences (NCBS).
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At least six institutes from Pune participated in the study, including the Indian Institute of Science Education and Research Pune (IISER), National Chemical Laboratory (NCL), National Centre for Cell Science (NCCS) and Pune Knowledge Cluster. The study found that Covishield demonstrated more robust immune responses compared to Covaxin.
The comprehensive study, carried out from June 2021 to January 2022, involved assessing 691 participants aged 18 to 45 years from Bangalore and Pune, India. It examined their vaccination records and monitored their immune responses at different intervals, both prior to and following vaccination.
“Follow-up studies on vaccine immunology and the analysis of immune protection factors were lacking and there’s a scarcity of comparative studies on these two vaccines. This is one of the very few studies that not only investigates the immune responses of participants after vaccination but also considers their immune history prior to vaccination,” said Dr Mangaiarkarasi Asokan, former programme head, VISION, and lead author of the study.
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IISER was one of the institutes from Pune in this research. Speaking about the institute’s role and the overall significance of this research, Vineeta Bal, emeritus professor, Biology, IISER Pune, said, “Part of the sample collection for this study was done in Pune. There were two hospitals in Pune from where the samples were collected, but the processing that was required thereafter was carried out between NCL and IISER, Pune. While there was a whole lot of talk going on about which vaccine performed better against the Covid-19 virus, for us in India, only two vaccines were available and the majority of citizens were vaccinated in a phase-wise manner.
However, there was no comparison data available about the performance and effectiveness of these vaccines. Some people only had data on Covaxin while others had data on Covishield. For the first time, this study has given us the comparative data for both vaccines. Moreover, the kind of technology established to study this aspect was not there in the country earlier. Hence, establishment of the technology will now be helpful for immunology assessment in future.”
Professor L S Shashidhara, centre director, NCBS, said, “This is the first-of-its-kind population-level immunological study on vaccines, post-deployment, particularly when the target virus is still spreading and evolving. Such studies need serum samples from diverse subjects representing genetic, geoclimatic and nutritional diversity and innovative study design and rigorous statistical methods. No one single organisation can undertake such a study.
We are grateful to all our partners and indebted to Hindustan Unilever for its generous funding. Results of this study so far and additional research that we are pursuing will have major inputs for future vaccine strategies as a public health programme.”
Key findings from the study
*Covishield, leveraging a virus vector to deliver the spike protein of the coronavirus, consistently demonstrated more robust immune responses compared to Covaxin, an inactivated virus vaccine. Notably, Covishield exhibited a near-complete immune response in the majority of participants, whereas the response to Covaxin was variable, particularly among those inoculated before the emergence of the Omicron variant.
*Covishield induced higher antibody levels in both seronegative (individuals without prior exposure) and seropositive (individuals with prior exposure) subjects, suggesting a more potent and enduring immune response.
*Covishield elicited a higher number of T cells compared to Covaxin, indicative of a stronger immune response.
*Covishield consistently exhibited higher levels of antibodies against various virus strains compared to Covaxin, suggesting its potential superior protection against variants such as Omicron.
