Sputnik Light booster after Sputnik V vaccination induces robust neutralizing antibody response to B.1.1.529 (Omicron) SARS-CoV-2 variant

COVID-19 vaccination campaign has been launched around the world. More than 8 billion vaccines doses have been administered, according to the WHO. Published studies shows that vaccination reduces the number of COVID-19 cases and dramatically reduces COVID-19-associated hospitalizations and deaths worldwide. In turn, the emergence of SARS-CoV-2 variants of concern (VOC) with mutations in the receptor-binding domain (RBD) of S glycoprotein poses risks of diminishing the effectiveness of the vaccination campaign. In November 2021, the first information appeared about a new variant of the SARS-CoV-2 virus, which was named Omicron. The Omicron variant is of concern because it contains a large number of mutations, especially in the S glycoprotein (16 mutation in RBD), which could be associated with resistance to neutralizing antibodies (NtAB) and significantly reduce the effectiveness of COVID-19 vaccines. Neutralizing antibodies are one of the important parameters characterizing the protective properties of a vaccine. We conducted a study of neutralizing antibodies in the blood serum of people vaccinated with Sputnik V, as well as those revaccinated with Sputnik Light after Sputnik V. Results showed that a decrease in the level of neutralizing antibodies was observed against SARS-CoV-2 Omicron (B.1.1.529) variant in comparison to B.1.1.1 variant. Analysis of the sera of individuals vaccinated with Sputnik V 6-12 months ago showed that there was a decrease in the level of neutralizing antibodies by 11.76 folds. While no direct comparison with other vaccines declines has been done in this study, we note their reported decline in antibody neutralization at a much more significant level of 40-84 times. At the same time, the analysis of sera of individuals who were vaccinated with Sputnik V, and then revaccinated Sputnik Light, showed that 2-3 months after revaccination the decrease in the level of neutralizing antibodies against the Omicron variant was 7.13 folds. Despite the decrease in NtAb, we showed that all revaccinated individuals had NtAb to Omicron variant. Moreover, the NtAb level to Omicron variant in revaccinated sera are slightly higher than NtAb to B.1.1.1 in vaccinated sera.

The rise and spread of the SARS-CoV-2 AY.122 lineage in Russia

BackgroundDelta has outcompeted most preexisting variants of SARS-CoV-2, becoming the globally predominant lineage by mid-2021. Its subsequent evolution has led to emergence of multiple sublineages, many of which are well-mixed between countries. AimHere, we aim to study the emergence and spread of the Delta lineage in Russia. MethodsWe use a phylogeographic approach to infer imports of Delta sublineages into Russia, and phylodynamic models to assess the rate of their spread. ResultsWe show that nearly the entire Delta epidemic in Russia has probably descended from a single import event despite genetic evidence of multiple Delta imports. Indeed, over 90% of Delta samples in Russia are characterized by the nsp2:K81N+ORF7a:P45L pair of mutations which is rare outside Russia, putting them in the AY.122 sublineage. The AY.122 lineage was frequent in Russia among Delta samples from the start, and has not increased in frequency in other countries where it has been observed, suggesting that its high prevalence in Russia has probably resulted from a random founder effect. ConclusionThe apartness of the genetic composition of the Delta epidemic in Russia makes Russia somewhat unusual, although not exceptional, among other countries.

One-shot immunization with Sputnik Light (the first component of Sputnik V vaccine) is effective against SARS-CoV-2 Delta variant: efficacy data on the use of the vaccine in civil circulation in Moscow

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.

The Value of Rapid Antigen Tests to Identify Carriers of Viable SARS-CoV-2.

The search for effective methods to detect patients who excrete a viable virus is one of the urgent tasks of modern biomedicine. In the present study, we examined the diagnostic value of two antigen tests BIOCREDIT COVID-19 Ag (RapiGEN Inc., Korea) and SGTI-flex COVID-19 Ag (Sugentech Inc., Korea) for their diagnostic value in identifying patients who excrete viable SARS-CoV-2. As part of the study, we examined samples from 106 patients who had just been admitted to the hospital, who had undergone quantitative RT-PCR and assessment of viability of SARS-CoV-2 using cell culture. Sensitivity was 0.786 (0.492-0.953) for SGTI-flex COVID-19 Ag and 1 (0.768- 1) for Biocredit COVID-19 Ag. Specificity of rapid tests was significantly higher than that of RT-PCR and was 0.663 (0.557-0.758) and 0.674 (0.568-0.768) for SGTI-flex COVID-19 Ag and Biocredit COVID-19 Ag versus 0.304 (0.213-0.409) obtained for PCR. Thus, for tasks of identifying viable SARS-CoV-2 during screening of conditionally healthy people, as well as monitoring those quarantined, rapid tests show significantly better results.