ABSTRACT
The recent vaccination campaign targeting the new coronavirus infection (COVID-19) carried out in the Armed Forces of the Russian Federation, on the background of the current unstable global pandemic situation, makes it necessary to study post-vaccination population immunity to the SARS-CoV-2 virus and thus identify key features of immunity in organized military collectives. In the future, this will make it possible to objectively assess the risks of a worsening pandemic situation, effectively adjust the ongoing sanitary and anti-epidemic measures aimed at preserving and strengthening the health of military personnel, as one of the main conditions for maintaining the combat readiness of the Armed Forces of the Russian Federation. During a study conducted on epidemic indications, it was found that vaccination with Gam-Covid-Vac contributes to the formation of collective immunity with 95% effectiveness. A gender-based analysis of the immune response showed that the proportion of persons who lack class G immunoglobulins to SARS-CoV-2 among females is twice than that among men (9.3% and 4.7%, respectively). Seroprevalence indicators, classified by blood group, range from 94.4% (AB (IV) Rh–) to 97.4% (A (II) Rh–). There were no significant differences in seroprevalence between groups of people with different blood groups;however, the highest value of seroprevalence was seen among military personnel with blood group A (II) Rh–. In this context, it is advisable to continue monitoring the formation of immunity in individuals with various blood groups. The results obtained made it possible to form a primary medical and social "portrait” of a serviceman with the most adequate immune response to the introduction of the Gam-Covid-Vac vaccine (a man under the age of 20 with blood type A (II) Rh–) and to draw a conclusion about the high effectiveness of vaccination in military units (formations) staffed by conscripts and military educational organizations. The article can be used under the CC BY-NC-ND 4.0 license © Authors, 2022.
ABSTRACT
In the context of the propagation of infectious diseases, when a sufficient degree of immunisation is achieved within a population, the spread of the disease is ended or significantly decreased, leading to collective immunity, meaning the indirect protection given by immune individuals to susceptible individuals. Here we describe the estimates of the collective immunity to COVID-19 from a stochastic cellular automaton based model designed to emulate the spread of SARS-CoV-2 in a population of static individuals interacting only via a Moore neighbourhood of radius one, with a view to analyze the impact of initially immune individuals on the dynamics of COVID-19. This impact was measured by comparing a progression of initial immunity ratio-the percentage of immunised individuals before patient zero starts infecting its neighbourhood-from 0 to 95% of the initial population, with the number of susceptible individuals not contaminated, the peak value of active cases, the total number of deaths and the emulated pandemic duration in days. The influence of this range of immunities over the model was tested with different parameterisations regarding the uncertainties involved in the model such as the durations of the cellular automaton states, the contamination contributions of each state and the state transition probabilities. A collective immunity threshold of 55 % ± 2.5 % on average was obtained from this procedure, under four distinct parameterisations, which is in tune with the estimates of the currently available medical literature, even increasing the uncertainty of the input parameters.
ABSTRACT
BACKGROUND: Longitudinal surveys to monitor the seroprevalence are required to support efforts for assessment of the levels of endemic stability in certain countries. We investigated seroprevalence of anti-SARS-CoV-2-S1 receptor-binding domain (RBD)-specific antibodies in the serum samples in 2011-2021, including a cohort study of 2019-2021, to evaluate the vaccination and anti-IgG-SARS-CoV-2-S1 RBD-positive statuses to assess the resistance and severity of COVID-19. MATERIALS AND METHODS: Anti-SARS-CoV-2-S1 RBD-specific antibodies were assayed in the serum samples (N = 565) randomly selected from various cohorts previously recruited from 2011 to 2021 from the city of Moscow and Moscow Region. Among them there were the participants (N = 310) recruited in 2019-2021 with an endpoint of 30 October 2021 when these participants were interviewed over phone with relevant questionnaire. RESULTS: Obtained data indicated a percentage of 3-6% of SARS-CoV-2-S1 RBD-specific antibodies detected in participants recruited in 2011-2019. The percentage of SARS-CoV-2-S1 RBD-specific antibodies was increased to 16.5% in 2020 and to 46% in 2021. The vaccination rate of 238 respondents of this cohort was 58% from August 2020 to October 2021. In total, 12% of respondents were hospitalized. The morbidity rate in the subgroup of anti-SARS-CoV-2-S1 RBD-positive respondents was 5.4-fold higher than that in the subgroup of vaccinated respondents. CONCLUSIONS: A small percentage of SARS-CoV-2-S1 RBD-specific antibodies detected in 2011-2019 indicated possible spreading of coronaviruses during the pre-pandemic period. Collective immunity in Moscow and the Moscow region was able to reach 69% from August 2020 to October 2021 if this rate is added to the rate of not vaccinated SARS-CoV-2-S1 RBD-positive subjects.
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As a tool for public health, the vaccination policy is based on the analysis of benefits and risks. Thus, the National Consultative Ethics Committee has been at the heart of the orientations taken in terms of the deployment of the vaccination against severe acute respiratory syndrome coronavirus 2, by contributing its reflections on the associated ethical issues.
Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19/prevention & control , Humans , VaccinationABSTRACT
Background. The need to study the population immunity to the SARS-CoV-2 virus is due to the intensive spread of COVID-19 and the implementation of immunoprophylaxis of this infection. The identification of the features of the formation of immunoresistance in organized military collectives will allow us to predict the development of the epidemic situation, including among comparable population groups. Aims ' the study of population immunity to the SARS-CoV-2 virus in the context of the COVID-19 pandemic against the background of specific immunoprophylaxis in organized military collectives. Methods. According to epidemiological indications, an epidemiological study of collective immunity to the SARS-CoV-2 virus was conducted against the background of vaccination among cadets of military educational organizations. The study involved 497 people, divided into groups by epidemiological and vaccination history for COVID-19, blood groups and Rh factor. The assessment of the immunity intensity was carried out by the levels of class G immunoglobulins (IgG) to SARS-CoV-2 in the blood serum by the method of solid-phase enzyme immunoassay. Results. Seroprevalence in the total sample was 92.6%. The highest rates were observed among vaccinated patients: those who were not ill and vaccinated ' 99.0 ± 0.7%, those who were ill and vaccinated-100% (mean geometric antibody titers ' 1:2234 and 1:4399). Among the ill, unvaccinated individuals, the seroprevalence index was 84.5 ± 3.2% (1:220). Among those who were not ill, not vaccinated ' 8.2 ± 3.1% (1:113), which may indicate a hidden course of the epidemic process in the team. A negative immune response was more common (tSt = 2.01;p < 0.05) in individuals A(II)Rh+ blood group. The highest proportion of maximum antibody titers (1:3200-1:6400) was determined in AB(IV) individuals. Rh-blood groups (tSt=2.21;p < 0.05). Conclusions. For the first time, the formation of combined immunity with the highest concentrations of specific antibodies was revealed in patients who have been ill and vaccinated has been revealed, which allows us to recommend vaccination to those who have suffered from COVID-19. The emergence of post-infectious immunity in organized groups with a latent epidemic process has been established. The relationship between the intensity of immunity with blood groups and the Rh factor was found. © 2021 Izdatel'stvo Meditsina. All rights reserved.
ABSTRACT
Background: Vaccine hesitancy can limit the benefits of available vaccines in halting the spread of COVID-19 pandemic. Previously published studies paid little attention to Arab countries, which has a population of over 440 million. In this study, we present the results of the first large-scale multinational study that measures vaccine hesitancy among Arab-speaking subjects. Methods: An online survey in Arabic was conducted from 14 January 2021 to 29 January 2021. It consisted of 17 questions capturing demographic data, acceptance of COVID-19 vaccine, attitudes toward the need for COVID-19 vaccination and associated health policies, and reasons for vaccination hesitancy. R software v.4.0.2 was used for data analysis and visualization. Results: The survey recruited 36,220 eligible participants (61.1% males, 38.9% females, mean age 32.6 ± 10.8 years) from all the 23 Arab countries and territories (83.4%) and 122 other countries (16.6%). Our analysis shows a significant rate of vaccine hesitancy among Arabs in and outside the Arab region (83% and 81%, respectively). The most cited reasons for hesitancy are concerns about side effects and distrust in health care policies, vaccine expedited production, published studies and vaccine producing companies. We also found that female participants, those who are 30-59 years old, those with no chronic diseases, those with lower level of academic education, and those who do not know the type of vaccine authorized in their countries are more hesitant to receive COVID-19 vaccination. On the other hand, participants who regularly receive the influenza vaccine, health care workers, and those from countries with higher rates of COVID-19 infections showed more vaccination willingness. Interactive representation of our results is posted on our project website at https://mainapp.shinyapps.io/CVHAA. Conclusions: Our results show higher vaccine hesitancy and refusal among Arab subjects, related mainly to distrust and concerns about side effects. Health authorities and Arab scientific community have to transparently address these concerns to improve vaccine acceptance. Funding: This study received no funding.