Covid-19 vaccine Sputnik V effective vs. Omicron variant

SPUTNIK V is twice more effective than the Pfizer vaccine in neutralizing activity against the Omicron - this is the main takeaway from the latest analysis by Italy’s Experimental Institute Lazzaro Spallanzani, Russia’s Gamaleya Research Center for Epidemiology and Microbiology and Moscow State Sechenov Medical University.

The researchers pitted Russia’s Gam-COVID-Vac jab, which is marketed around the world as Sputnik V, and Pfizer-BioNTech COMIRNATY mRNA vaccine against each other in a comparative preprint study, which has been published by the well-known MedRxiv portal – a global hub for medical, clinical and related health sciences. The goal was to explore the efficacy of the two COVID-19 vaccines against the Omicron variant.

The examination has been done by the 12 Italian scientists in a lab setting in Rome, using blood serum samples of persons vaccinated with these jabs, who had similar levels of IgG (immunoglobulin G) antibodies and the same neutralizing activity against the initial variant of novel coronavirus registered in Wuhan, China.

The group’s findings show that in comparison with the Pfizer jab, Sputnik V had 2,1 times more neutralizing antibodies against the Omicron in general, and 2,6 times more antibodies three months after vaccination.

When it comes to in-depth analysis of protection mechanisms, researchers noted that Sputnik V neutralizes the Omicron variant because it forms a stronger immune response due to the high level of antibodies. When reviewing the basic level of RBD (receptor-binding domain)-specific IgG antibodies, researchers pointed that within the upper 25% of samples with highest levels of IgG, 100% of individuals vaccinated with Sputnik V had these antibodies, compared to 83.3% in the Pfizer group. In total 74,2% of Sputnik V blood serum samples successfully neutralized the Omicron compared to 56,9% for Pfizer.

As to reasons why Sputnik V forms such an immense response to Omicron, there are several factors at play, such as producing a much broader specter of neutralizing antibodies, whilst the Pfizer jab uses the S-protein in proline-stabilized form aimed against specific parts of the antigen molecules, which, in case of the Omicron are usually deformed by virus’s mutations. Sputnik V’s heterologous prime boost technology also plays a role, with Russian vaccine using two different carrier adenovirus vectors, with human adenoviral vector platform itself having an additional advantage of better imitation of the infection. The Spallanzani-Gamaleya MedRxiv publication mentions this approach as the most effective one:

The Sputnik Light vaccine is based on the human adenovirus serotype 26, which is also used as the first component of the two-dose Sputnik V. Plans for its production have been announced by manufacturers  in countries such as China and India, South Korea and Vietnam, Serbia, Mexico, Argentina and Turkey. Among facilities on the list is the Serum Institute of India, which is known as the world’s largest vaccine producer.

RDIF – the Russian Direct Investment Fund, is the country's sovereign wealth fund, established to make equity co-investments, primarily in Russia, alongside international strategic and financial investors. is in charge of Sputnik V and Sputnik Light’s production and international distribution.

RDIF CEO Kirill Dmitriev has underlined the importance of the Russian vaccine in providing protection against the Omicron, which has been confirmed by the Spallanzani-Gamaleya study: “The adenoviral vector platform has already shown high efficacy in combatting coronavirus mutations in the past. Heterogenous boosting with the use of Sputnik Light could raise the effectiveness of other vaccines, and partnership between various vaccine platforms plays a key role in light of challenges created by the simultaneous presence of Delta and Omicron variants.”

Sputnik V is authorized for use in 71 countries with a total population of 4 billion people. The Omicron variant of SARS-Cov-2 has been identified in November of 2021 and has rapidly become the dominant type of the novel coronavirus around the world. The Omicron has been detected in at least 150 countries. (Mark Navales and Malou Cablinda contributed to this report.)