· A unique comparative study conducted at the Italian Spallanzani Institute, the leading Italian research institute for infectious diseases, by a joint Italian-Russian team of researchers representing the Institute and the Gamaleya Center shows that the Sputnik V coronavirus vaccine demonstrates higher titers of virus-neutralizing antibodies to Omicron (B.1.1.529) variant than 2 doses of Pfizer vaccine (2.1 times higher in total and 2.6 times higher 3 months after vaccination).
o The study was conducted in equal laboratory conditions in the Spallanzani Institute in Italy on comparable sera samples from individuals vaccinated with Sputnik V and Pfizer with a similar level of IgG antibodies and virus-neutralizing activity (VNA) against Wuhan variant.
o Sputnik V shows significantly smaller (2.6 times) reduction of virus neutralizing activity against Omicron as compared to reference Wuhan variant than Pfizer vaccine (8.1-fold reduction for Sputnik V in contrast to 21.4-fold reduction for Pfizer vaccine).
· The study demonstrates that Sputnik V neutralizes the Omicron variant by inducing robust antibody response associated with high levels of protection.
Among the top quartile of individuals with high RBD-specific IgG antibodies, 100% of those vaccinated with Sputnik V were able to neutralize Omicron variant in comparison to 83.3% of individuals vaccinated with Pfizer.
Among all samples, 74.2% of Sputnik V-vaccinated sera were able to neutralize Omicron vs 56.9% for Pfizer-vaccinated.
· The study discusses several reasons for Sputnik V eliciting stronger virus neutralizing antibodies against Omicron, including:
o Sputnik V develops a wider pool of antibodies to different epitopes in contrast to Pfizer vaccine, which utilizes the spike protein in a proline-stabilized form directed mainly to the specific epitopes, which were highly affected by the mutations in the Omicron variant;
o Heterologous prime-boost vaccination regimen of Sputnik scheme;