Revaccination in Age-Risk Groups with Sputnik V Is Immunologically Effective and Depends on the Initial Neutralizing SARS-CoV-2 IgG Antibodies Level

Abstract

Vaccination against COVID-19 has occurred in Russia for more than two years. According to the Russian official clinical guidelines to maintain tense immunity in the conditions of the ongoing COVID-19 pandemic, it is necessary to use booster immunization six months after primary vaccination or a previous COVID-19 contraction. It is especially important to ensure the maintenance of protective immunity in the elderly, who are at risk of severe courses of COVID-19. Meanwhile, the immunological effectiveness of the booster doses has not been sufficiently substantiated. To investigate the immunogenicity of Sputnik V within the recommended revaccination regimen and evaluate the effectiveness of booster doses, we conducted this study on 3983 samples obtained from individuals previously vaccinated with Sputnik V in Moscow. We analyzed the level of antibodies in BAU/mL three times: (i) six months after primary immunization immediately before the booster (RV), (ii) 3 weeks after the introduction of the first component of the booster (RV1), and (iii) 3 weeks after the introduction of the second component of the booster (RV2). Six months after the primary vaccination with Sputnik V, 95.5% of patients maintained a positive level of IgG antibodies to the receptor-binding domain (RBD) of SARS-CoV-2. The degree of increase in the specific virus-neutralizing antibodies level after revaccination increased with a decrease in their initial level just before the booster dose application. In the group of people with the level of antibodies up to 100 BAU/mL six months after the vaccination, a more than eightfold increase (p < 0.001, Wilcoxon criterion with Bonferroni adjustment) in the level of specific antibodies was observed (Me = 8.84 (IQR: 3.63–30.61)). A significant increase in the IgG level after receiving both the first and the second booster doses occurred at the initial titer level up to 300 BAU/ mL (p < 0.001) in those who did not contract COVID-19 in the past and up to 100 BAU/mL (p < 0.001) in those who were previously infected with SARS-CoV-2. A significant increase in the antibody level after the first dose of the booster was noted for people who had up to 500 BAU/mL (p < 0.05), regardless of the previous COVID-19 infection. Thus, revaccination is most effective in individuals with an antibody level below 500 BAU/mL, regardless of the vaccinee age and COVID-19 contraction. For the first time, it has been shown that a single booster dose of the Sputnik vaccine is sufficient to form a protective immunity in most vaccinees regardless of age and preexisting antibody level.

Longitudinal Follow-Up of the Immunity to SARS-CoV-2 in Health Care Workers in Argentina: Persistence of Humoral Response and Neutralizing Capacity after Sputnik V Vaccination

“…Correlation of anti-Spike/RBD antibody levels and neutralizing antibody titers was previously reported ( 6 to 12 ). Here, we evaluated correlation in the Non-COVID group by analyzing levels of specific antibodies and neutralizing antibodies against ancestral SARS-CoV-2.…”

“…The magnitude of the drop is comparable for both adenovirus and mRNA-based vaccines and was is in the range of 2- to 10-fold decrease between peaking of antibody response (2 to 3 weeks after completion of the vaccination schemes) and 6 months ( 24 , 34 , 35 ). In addition, antibody titers are induced to a similar higher extent in individuals that acquired COVID-19 prior to vaccination compared to naive individuals ( 24 , 34 ), and breakthrough infection boosts the antibody response for both platforms ( 12 , 14 , 15 , 36 ). Finally, partial escape to vaccine-induced antibodies of VOCs Gamma and Delta as assessed by the fold reduction in neutralization titers is also a common feature ( 25 ) and suggests that the continued emergence of VOCs impacts the breadth of protection conferred by vaccination.…”

“…Overall, our work provides comprehensive information regarding the response induced by Sputnik V vaccination by means of an analysis that comprised more than 1,100 individuals and the follow-up of more than 500 fully vaccinated individuals. We showed that humoral/neutralizing response persists after Sputnik V vaccination and that neutralizing capacity decreases over time if no further immunization (natural or by a vaccine boost) may occur ( 12 ), highlighting the importance of administering a complete scheme and booster doses in the medium term to keep neutralizing titers both in naive and vaccinated-infected individuals. Likewise, Sputnik V has been approved for use in 71 countries, including several countries in Latin America, and although the global political context has paralyzed the verification by the WHO of the efficacy of this vaccine, our work adds new clear and necessary evidence regarding the response mounted by Sputnik V.…”

“…However, data on maintenance of seropositivity is divergent. Although seroprevalence after 2 to 3 weeks after second dose is generally 97 to 99%, some works showed that seropositivity decreased over a 6-month period to 83% ( 6 ) and even to 31% ( 11 ), whereas some others reported a maintenance of seropositivity in around 95% of the analyzed cohort ( 7 , 9 , 12 ).…”

Antigenic Cartography Indicates That the Omicron BA.1 and BA.4/BA.5 Variants Remain Antigenically Distant to Ancestral SARS-CoV-2 after Sputnik V Vaccination Followed by Homologous (Sputnik V) or Heterologous (Comirnaty) Revaccination

“…The Sputnik V booster did not result in increased antibody levels in a subgroup of individuals who had recovered from COVID-19 1–4 months prior to a booster. Previously, for Sputnik V revaccination, it was shown that the magnitude of a boost-induced increase in the antibody levels depended on the initial level of antibodies at the time of revaccination [ 24 ]. This effect may have been related to the presence of high levels of specific anti-S antibodies and T-cells, which were sufficient to neutralize the antigen induced by the booster.…”