The Gamaleya National Research Center of Epidemiology and Microbiology (Gamaleya Center) and the Russian Direct Investment Fund (RDIF, Russia’s sovereign wealth fund, investor in Sputnik V and Sputnik Light coronavirus vaccines), Thursday announced a unique independent comparative study conducted at the National Institute for Infectious Diseases Lazzaro Spallanzani (Italy) by a joint team of researchers of the Institute and the Gamaleya Center showing that 2 doses of Sputnik V provide more than 2 times higher geometric mean titers (GMT) of virus neutralizing antibodies to the Omicron variant of COVID than 2 doses of Pfizer vaccine (2.1 times higher in total and 2.6 times higher 3 months after vaccination).

An article by a team of 12 Italian and 9 Russian scientists led by Francesco Vaia, Director of the Spallanzani Institute and Alexander Gintsburg, Director of the Gamaleya Center, has been published in medRxiv (the preprint server for health sciences).

The study was conducted in Spallanzani Institute in the equal laboratory conditions at the Italian Spallanzani Institute on comparable groups of sera from individuals vaccinated with Sputnik V and Pfizer, with no statistically significant difference in neutralizing activity against Wuhan variant.

The advantages of Sputnik V are the use of native S glycoprotein (spike protein without proline-stabilization and other modifications) and the use of a heterologous prime-boost vaccination regimen. The Pfizer vaccine utilizes the spike protein in a proline-stabilized form in contrast to Sputnik V. Proline-stabilization and other modifications may move an immune response predominantly to the actively mutating receptor-binding domain (RBD) of spike protein. In the Omicron variant, a substantial number of mutations were registered precisely in RBD, which is why such a significant drop in neutralizing activity against this variant may be observed in the sera of Pfizer-vaccinated.

Boosting with Sputnik Light as part of the “mix & match” approach may help address the lower efficacy of mRNA vaccines against Omicron as well as the documented, quickly waning, efficacy of mRNA vaccines against COVID-19. Partnerships between adenoviral and mRNA vaccines could provide for stronger protection against Omicron and other variants.

Based on the data collected by the Spallanzani Institute and results of previous studies, heterologous (“mix & match”) boosting with Sputnik Light is the best solution to increase other vaccines’ efficacy and extend the booster protection period as optimal adenoviral platform configuration provides better protection against Omicron and other mutations:

a. Sputnik Light as a booster significantly increases virus neutralizing activity against Omicron, which is comparable to titers observed after Sputnik V against wild-type virus, associated with high levels of protection.

b. Sputnik Light has already shown strong results as a booster in “mix & match” trials in Argentina. A combination of Sputnik Light with vaccines produced by AstraZeneca, Sinopharm, Moderna and Cansino, conducted in 5 provinces (City and Province of Buenos Aires, as well as Córdoba, La Rioja and San Luis) has demonstrated that Sputnik Light induces stronger antibody and T-cell response as compared to a homologous regimen (two shots of the same vaccine). Each “vaccine cocktail” combination with Sputnik Light provided higher antibody titer on the 14th day after administering a second dose when compared to original homologous (same vaccine as first and second dose) regimens of each of the vaccines.

c. As duration of vaccine protection is key to avoid frequent boosting, authors of another study in Argentina have noted that protection against coronavirus remains stable following vaccination with the Russian Sputnik V vaccine as a consequence of antibody maturation, resulting in improved potency of antibodies to viral escape mutations.

d. The study conducted by a number of highly respected institutes in the US (Beth Israel Deaconess Medical Center, Harvard University, Ragon Institute of MGH, MIT and University of North Carolina) demonstrated that boosting Pfizer vaсcine with Ad26 vector produces optimal durable protection against Omicron with 4 times higher increase in Omicron-specific T-cells and 2.4 times in neutralizing antibody titers vs Pfizer booster. Sputnik Light is based on Ad26 vector and is the universal booster for other vaccines vs all mutations.

e. US study on 168 mln people showed that one-shot COVID vaccine based on Ad26 is superior against infections and hospitalizations to quickly waning two-shot mRNA vaccines. In the 6th month after vaccination, Pfizer protection against hospitalization waned 4 times, while there was no evidence of waning protection against hospitalization for Ad26 vector.

f. Another study conducted on almost 500,000 health care workers in South Africa demonstrated 85% efficacy of Ad26 booster against hospitalization caused by Omicron variant.

Partnership among vaccine manufacturers through heterologous (“mix & match”) boosting by other vaccines is needed to address the quickly waning efficacy of mRNA vaccines against COVID-19, which was documented in multiple studies:

a. The study in US among 65+ years old population demonstrated the decrease in mRNA vaccine effectiveness against Delta accelerated after month 4, reaching a low of approximately 20% in months 5 through 7.

b. According to Swedish data, the Pfizer vaccine’s efficacy against Delta strain is falling to below 30% after 6 months.

c. The UK Health Security Agency said those who had received three doses of Pfizer’s vaccine saw their protection against symptomatic illness caused by Omicron variant drop to 45% within 10 weeks.

Alexander Gintsburg, Director of the National Research Center for Epidemiology and Microbiology, said: “The joint study by the Gamaleya Center and Spallanzani Institute confirmed the results obtained in our separate study published in December 2021. The hard scientific data proves Sputnik V has higher virus neutralizing activity against Omicron as compared to other vaccines and will play a major role in the global fight against this new contagious variant.”

Denis Logunov, Deputy Director of the National Research Center for Epidemiology and Microbiology, noted: “The Spallanzani Institute is one of the leading European research centers and our joint study provided a unique opportunity for independent analysis of different vaccine platforms against Omicron. Adenoviral vector platform in the core of Sputnik V and Sputnik Light vaccines once again proved to be the best solution in creating strong and durable immunity against COVID and its new variants.”

Kirill Dmitriev, CEO of the Russian Direct Investment Fund, commented: “Results of the study in Italy confirm Sputnik V offers the strongest protection against Omicron. The adenoviral platform has shown high efficacy in fighting mutations of COVID previously. Partnership of different platforms is the key and heterologous (“mix & match”) boosting with Sputnik Light will help strengthen efficacy of other vaccines in light of combined Delta and Omicron challenge.”