A small study claims that Covaxin offers protection from both the delta (B.1.617.2) and beta (B.1.351) variants.
The study evaluated the neutralisation potential in people vaccinated with Covaxin and found that there was a 3- and 2.7-fold reduction in neutralisation titers against the beta (B.1.351) and delta (B.1.617.2) variants, respectively. In comparison, the reduction in neutralisation titers with sera from people who have recovered from COVID-19 were 3.3- and 4.6-fold against the beta and delta variants, respectively. The results of the study were posted on the bioRxiv preprint server on June 7. Preprints are yet to be peer-reviewed.
“We observed a reduction in neutralisation titer values in Covaxin recipients against the beta and delta variants but the reduction is less than in people who have been naturally infected. So the vaccine does offer protection against the two variants,” says Dr. Pragya Yadav from the Pune-based National Institute of Virology and the first author of the preprint. The study was carried out by researchers from NIV, ICMR and Bharat Biotech.
The study evaluated the neutralisation potential of sera collected from 20 COVID-19 recovered cases and 17 people vaccinated with two doses of Covaxin against the beta and delta variants and compared it with the prototype D614G variant. “Many other studies investigating the neutralisation potential of sera collected from people administered different vaccines too have used only a small number of samples,” says Dr. Yadav.
The researchers assessed the neutralisation potential of sera from COVID-19 recovered cases after 5-20 weeks of infection and 28 days after two doses in the case of Covaxin recipients. Seventeen of the recovered cases were infected with D614G variant and three were infected with B.1.617.1 lineage.
All COVID-19 vaccines currently used, including Covaxin, have been found to offer relatively lower protection against the beta variant. In comparison, all vaccines offer relatively higher protection against the delta variant.