Covaxin (BBV152) Vaccine Neutralizes SARS-CoV-2 Delta and Omicron variants

The SARS-CoV-2 vaccine BBV152/Covaxin is well-tolerated and was shown to be 77.8% efficacious against symptomatic and 93.4% efficacious against severe symptomatic COVID-19 disease in adults. Previous studies have shown that sera from Covaxin vaccinated individuals have neutralizing activity against B.1.1.7 (Alpha), B.1.351 (Beta), B.1.617.2 (Delta), B.1.1.28 (Zeta), and B.1.617.1 (Kappa) SARS-CoV-2 variants. The B.1.1.529 variant (Omicron) recently emerged in November 2021 and has spread throughout the world. The Omicron variant has more than 30 mutations within the spike protein that could impact vaccine-mediated immunity. We used a live virus neutralization assay to evaluate the neutralizing activity against the Omicron variant of sera collected from subjects who received a booster dose (6-month after primary series last dose) of Covaxin. We found that sera from Covaxin boosted individuals showed neutralizing activity against D614G (vaccine strain), Delta, and Omicron variants. One hundred percent of boosted subjects showed neutralizing activity against the Delta variant while over 90% of boosted subjects showed neutralizing activity against the Omicron variant. These findings show that a booster dose of Covaxin can generate robust neutralizing antibody responses against the Omicron variant.