ABSTRACT
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.
ABSTRACT
ObjectivesVaccination remains the most effective response to the COVID-19 pandemic. Most vaccines use two-dose regimens. In turn, single-dose vaccines also have high potential, since, on the one hand, they simplify the vaccination program, make it more accessible and convenient for more people around the world, and on the other hand, they are better suited for subsequent revaccination. However, there is not enough data on the effectiveness of single-dose vaccine variants against new genetic lines to assess their current potential. It is not clear how much a single dose of immunization protects against the globally dominant delta variant. In this work, we investigated the effectiveness of a single dose vaccine (Sputnik Light, the first component of Sputnik V vaccine) against the Delta variant in Moscow. MethodsTo assess the effectiveness of one dose of viral vector vaccine based on rAd26 against the delta variant in Moscow, we used data from the Moscow registries of vaccination against COVID-19 and the incidence of COVID-19. The availability of data on the number of seropositive residents of Moscow made it possible to consider the size of the immune layer formed because of a previous COVID-19 disease or vaccination. To calculate the effectiveness, the proportion of COVID-19 cases among those vaccinated with a single dose and the proportion of cases among those who were not vaccinated in July 2021. ResultsOur data indicate that throughout July 2021, the dominant variant of the coronavirus at the level of 99.5% in Moscow was the SARS-CoV-2 delta variant and its subsidiary lines. Considering the immune layer of 46% allowed us to calculate the effectiveness of a one-shot vaccine against the delta variant in Moscow during the first three months after vaccination at the level of 69.85% (95% confidence interval [CI], 64.08 to 74.70). In the 18-29-year-old group, the overall vaccine efficacy against the delta variant was 88.61%, in the 18-59 group - 75.28%. Sputnik Light demonstrates higher efficacy against Delta variant than many two-shot vaccines. ConclusionThe results indicate a high efficacy of a single immunization first component of Sputnik V vaccine against delta variant among young and middle-aged people, at least during the first 3 months after receiving the one-shot vaccine.
