Health News: There have been several views regarding which vaccine among the two – Covishield or indigenously made Covaxin – is better. We apparently have an answer to this now as a multi-center study has found that neutralising antibody responses against the SARS-COV-2 virus and its variants of concern (VoC) are higher among those who received Covishield than those who took Covaxin.
The study, which is yet-to-be peer-reviewed, has been posted on the preprint server MedRxiv on Friday. According to the study, both vaccines elicited statistically significant antibody levels in both seronegative individuals and seropositive or those who had recovered from Covid-19 infection when compared to the pre-vaccination baseline.
For the study, 691 participants in the 18-45 age group were enrolled between June 2021 and January 2022 were enrolled. They were enrolled across four sites in urban and rural Bengaluru and Pune.
Those who were part of the study either received two doses of Covaxin at 28 days apart or two doses of Covishield at three months apart.
The Omicron wave in early 2022 overlapped with the second dose of vaccine in two sites and with both doses in one site.
Participants were sampled at six timepoints for antibody analyses and at four timepoints for cellular analyses.
When compared to pre-vaccination baseline, both vaccines elicited statistically significant antibody levels in both seronegative and seropositive individuals, the researchers found.
Covishield elicited immune responses of higher magnitude and breadth than Covaxin in both seronegative individuals and seropositive individuals, across cohorts representing the pre-vaccination immune history of the majority of the vaccinated Indian population.
According to immunologist Vineeta Bal, in young adult population there’s a difference in the response to Covid vaccines, if individuals are already infected with SARS-CoV-2 and recovered (seropositives) versus not infected.
“In seronegatives, two doses of Covishield lead to higher magnitude of antibody levels in higher proportion of vaccine recipients as compared to Covaxin recipients,” Bal said. Bal is from the Indian Institute of Science Education and Research (IISER), Pune and one of the study authors.
“In terms of the waning of immune response with time also Covishield vaccinated individuals retain antibodies in their blood for a longer period in a larger proportion of individuals,” she added.