Retention of Neutralizing response against SARS-CoV-2 Omicron variant in Sputnik V vaccinated individuals

The new variant Omicron (B.1.1.529) of SARS-CoV-2, first identified in November 2021, is rapidly spreading all around the world. The Omicron becomes the dominant variant of SARS-CoV-2. There are many ongoing studies evaluating the effectiveness of existing vaccines. Studies on neutralizing activity of vaccinated sera against Omicron variant are currently being carried out in many laboratories. In this study, we have shown the neutralizing activity of sera against SARS-CoV-2 Omicron (B.1.1.529) variant compared to the reference Wuhan D614G (B.1) variant in individuals vaccinated with 2 doses of Sputnik V or BNT162b2 in different time points up to 6 months after vaccination. We performed analysis on sample pools with comparable NtAb to Wuhan D614G variant. The decrease in neutralizing antibody (NtAb) to the Omicron variant was 8.1 folds for group of Sputnik V-vaccinated and 21.4 folds for group of BNT162b2-vaccinated. Analysis showed that 74.2% of Sputnik V- and 56.9% of BNT162b2-vaccinated sera had detectable NtAb to SARS-CoV-2 Omicron variant. The decrease in NtAb to SARS-CoV-2 Omicron variant compared to Wuhan variant has been shown for many COVID-19 vaccines in use, with some showing no neutralization at all. Today the necessity of third booster vaccination is obvious. And the most effective approach, already shown in several studies, is the use of heterologous booster vaccination pioneered in COVID-19 vaccines by Sputnik V.