Covishield and Covaxin, which is effective at generating an immune response against Covid-19, appear to generate only half as many antibodies against the B.1.617 strain which was first detected in Maharashtra, according to early reports from scientists at the Indian Council of Medical Research (ICMR). Several scientists said that this drop didn’t diminish the fact that the vaccines continued to be potent tool against Covid-19.
Scientists at the ICMR-National Institute of Virology (NIV), Pune have been collecting samples from Covid-positive patients and testing them for prominent variants like B.1.1.7 (UK variant), the B.1.351 (South Africa variant), the P2 (Brazil variant) and B.1.617 since January. But the related variants of the B.1.617 now make up an increasing proportion of cases in India, a report in The Hindu said.
The two vaccines- Covaxin and Covishield- being administered in India, were designed on the blueprint of the virus variant, called B1, that became the dominant strain in India by last April.
After reports emerged from vaccine trials across the globe showed that certain mutations in the virus helped it evade immune systems and antibodies, several labs have been working to check the potency of vaccines against emerging variants.
NIV scientists tested the virus with B.1.617 mutations, on antibodies that were extracted from the blood serum of those with two doses of Covaxin, they found roughly 55% lesser antibodies than the antibodies generated against B.1.
In case of Covishield, the antibody levels for B.1.617 it was 21.9 percent while it was 42.92 percent for the B.1 variant, again roughly half.
The report added that when antibody levels were compared against the B.1.1.7 (UK strain), there was only a 6 percent reduction whereas against Brazilian strain (P2) there was again a percent reduction.
“While the reductions were roughly on these lines, they showed that both Covishield and Covaxin were almost similarly protective against the B.1.617,” Dr Samiran Panda, who heads the Epidemiology Division at the ICMR, Delhi and co-author of the paper reportedly said.
However, some scientists say that a two-fold reduction wasn’t serious at all. “A ten fold or greater level of reduction may be important but then again different labs have varying approaches to conducting such tests,” Rakesh Mishra, former Director, Centre for Cellular and Molecular Biology (CCMB) said.