SARS-CoV-2 Herd Immunity of the Kyrgyz Population in 2021

Background. In the fight against coronavirus infection, an important direction is control of herd immunity to the pathogen. SARS-CoV-2 herd immunity is formed naturally as a result of manifest or asymptomatic infection, or artificially as a result of vaccination Aim: To assess the SARS-CoV-2 herd immunity status of the Kyrgyz population. Materials and methods. A cross-sectional, randomized study of SARS-CoV-2 herd immunity was carried out according to a program developed by Rospotrebnadzor, with the participation of the Saint Petersburg Pasteur Institute, taking into account WHO recommendations. In all study stages cloud service (internet) technologies were used. The ethics committees of the Preventive Medicine Association (Kyrgyzstan) and the Saint Petersburg Pasteur Institute (Russia) approved the study. A total of 9,471 volunteers were selected, representing 0.15% (95% CI 0.14-0.15) of the total population. They were randomized according to age and region. Antibodies (Abs) to the nucleocapsid antigen (Nag) were determined by enzyme-linked immunosorbent assay (ELISA) of volunteer blood plasma. For vaccinated individuals, Abs to the SARS-CoV-2 receptor-binding domain antigen (RBDag) were determined. Statistical processing of the results was carried out using Excel 2010 and other programs. Differences were designated as statistically significant at p<0.05. Results. The seroprevalence of the general population was 48.7% (95% CI 47.7-49.7), with a maximum in the group of '60-69 year old' (59.2% (56.6-61.7)) and a minimum in the group '1-17 y.o.' (32.7% (95 CI 29.4-36.1)). The largest proportion seropositive was found in the Chui region (51.3% (95% CI 47.9-54.8)). The lowest was in Osh city (38.1% (95 CI 32.6-43.9)). The maximum seropositivity was detected among healthcare workers (57.1% (95% CI 55.4-58.8); the minimum was noted among artists (38.6% (95% CI 26.0-52.4)). Asymptomatic SARS-CoV-2 positivity was 79.1% (96% CI 77.9-80.3). Vaccination with Sputnik V, EpiVacCorona, or Sinopharm formed comparable levels of immunity. Conclusions. The herd immunity to SARS-CoV-2 Nag is 48.75% (95% CI 47.7-49.7), and the overall immunity (Nag + RBDag) is 57%.

Herd immunity to SARS-COV-2 in the population of the Southern regions of the Far East of Russia

The aim: to study the structure and dynamics of population immunity to SARSCoV-2 of the population of the Southern Regions of the Far East (SRFE): Khabarovsk, Primorsky Krai and Amur Region during the COVID-19 epidemic in 2020.Materials and methods. The work was carried out according to the program for assessing population immunity to SARS -CoV-2 of the population of the Russian Federation according to the methodology developed by the Rospotrebnadzor with the participation of the St. Petersburg Pasteur Institute. The study was approved by the ethical committee of the St. Petersburg Pasteur Institute. The selection of participants was carried out by a questionnaire method using cloud technologies. The volunteers were randomized by age by stratification into 7 age groups: 1–17, 18–29, 30–39, 40–49, 50–59, 60–69, 70+ years old. Territorial randomization consisted in limiting the engaging of volunteers – no more than 30 people from one enterprise. After the initial cross-sectional study, a 3-stage seromonitoring was carried out, in which the same volunteers participated. Antibodies to the SARS-CoV-2 nucleocapsid were determined in peripheral blood serum by the enzyme immunoassay using an appropriate set of reagents produced by the State Scientific Center for Medical and Biological Sciences of the Rospotrebnadzor (Obolensk). Statistical analysis was performed using the Excel package. The confidence interval for the proportion was calculated using the A. Wald, J. Wolfowitz method with A. Agresti, B.A. Coull’s correction. The statistical significance of the differences was calculated online using a specialized calculator. The statistical significance of the differences was assessed with a probability of p˂ 0.05, unless otherwise indicated.Results. In a comparative analysis, the highest morbidity was observed in the Khabarovsk Territory, the lowest – in the Primorsky Territory. The level of seroprevalence among the population of the region was 19.6 % (95 % CI: 18.2–21.1) in the Khabarovsk Territory, 19.6 % (95 % CI: 18.1–21.2) in the Primorsky Territory19,6 % and 45,5 % (95 % CI: 43.7–47.3) in the Amur region. The highest seroprevalence was noted among 1–17 years old children, mainly due to the subgroup of 14–17-years-olds. The smallest proportion of seropositive was found among 40–49-year-olds in the Khabarovsk Territory (14.7 %, 95 % CI: 11.2–18.6), 18–28-yearolds in the Primorsky Territory (13.3 %, 95 % CI: 10.0–17.1) and 30–39-year-olds in the Amur Region (36.3 %, 95% CI: 31.7–41.6). No statistically significant dependence of seroprevalence on territorial and occupational factors has been established, with the exception of an increase in the proportion of seropositive medical workers in Primorsky Territory. In the process of 3-stage seromonitoring, a regular increase in the proportion of seropositive people was revealed in all SRFE. The resulting tendency is correctly described by a second-order polynomial. A relationship was revealed between the number of convalescents and persons in contact with them, which made it possible to calculate the base reproductive number (R0) in the range from 1.4 (Primorsky Territory) to 2.4 (Amur Region). Analysis of seroprevalent volunteers showed that the number of asymptomatic individuals varied from 94.1 % (95 % CI: 92.8–95.3) to 98.3 % (95 % CI: 98.8–99.2). This indicates that most of the volunteers had COVID-19 asymptomatically.Conclusions. A comparative study showed the prevalence of seroprevalence in the Amur Region compared with the Khabarovsk and Primorsky Territories. The relationship between the number of convalescents and persons in contact with them was noted. The value of the base R0 is calculated. It has been shown that more than 90 % of seropositive individuals in the COVID-10 SRFE were asymptomatic.

Herd immunity to SARS-CoV-2 among the population of the Republic of Belarus amid the COVID-19 pandemic

Objective was to investigate the SARS-CoV-2 collective immunity status of the population of Belarus within the context of the COVID-19 pandemic. Materials and methods. The work was carried out according to the methodology for assessing SARS-CoV-2 population immunity, developed by Rospotrebnadzor Russia and the Ministry of Health of Belarus with the participation of the St. Petersburg Pasteur Institute, taking into account WHO recommendations. The Bioethics Committee of Belarus and the local ethics committee of the St. Petersburg Pasteur Institute approved the study. Selection of participants was carried out using a questionnaire method and online technology (internet, cloud server). Volunteers were randomized into seven age groups (years of age): 1–17; 18–29; 30–39; 40–49; 50–59; 60–69; and 70+. Regional randomization ensured proportional representation of volunteers from each region, and no more than 30 people were included from one enterprise. In accordance with manufacturer instructions, blood plasma samples were analyzed for: IgG antibodies (Abs) to the SARS-CoV-2 nucleocapsid (Nc) using a quantitative ELISA test system; and IgG Abs to the receptor binding domain (RBD) of the SARS-CoV-2 S (spike) surface glycoprotein using a qualitative ELISA test system. Statistical processing was carried out using Excel 2010 and other software. Statistical differences were designated as significant when p < 0.05, unless otherwise indicated. Results. The level of seroprevalence, in terms of Abs to Nc among the Belarusian population, was 38.4% (95% CI 37.6–45.4). The highest Ab levels were found among individuals in older age groups (50-70+ years old). The lowest were found in children 1–17 years old and in young people 18–39 years old The distribution of seroprevalence across Belarusian regions was relatively homogeneous, with the exception of the Minsk Region, where a statistically significant decrease in the indicator was noted. In terms of profession, the largest share of seropositive individuals was found among transportation workers; the smallest was found in business. The moderate COVID-19 incidence has not led to a dramatic increase in the number of contacts. The base reproduction number (R0) was 1.3. In the Republic of Belarus, there was a moderate level of asymptomatic COVID-19 among seropositive individuals (45.3% [95% CI 44.0–46.7]). This form of infection was observed most often among children aged 1–17 years old (65.0% [95% CI 61.3–68.6]). In parallel with seroprevalence assessment, SARS-CoV-2 vaccination was carried out. We used two vaccines: Gam-COVID-Vac (also known as Sputnik V, developed by Gamaleya National Center for Epidemiology and Microbiology, Russia); and BBIBP-CorV (Sinopharm, PRC). Vaccination against SARS-CoV-2 was accompanied by an increase in the level of anti-RBD Abs (95% [95% CI 94.7–96.7]). Taking into account the vaccination of a subset of the population with BBIBP-CorV, the overall herd immunity, inferred from the analyzed indicators (presence of anti-Nc or anti-RBD Abs), was 47.1% (95% CI 46.3–48.0). Conclusion. COVID-19 in Belarus was characterized by a moderately pronounced course of the epidemic process. The threshold level of herd immunity to SARS-CoV-2 has not yet been reached, as a result of which the conditions for progression of the epidemic remain.

Case of parvovirus B19 infection and immunodeficiency in the patient with Gilbert syndrome

A case of long-term persistence of parvovirus B19 is described for the first time in a patient with Gilbert's syndrome against the background of immunodeficiency with predominance of infectious symptoms (chronic herpesvirus infection). Previously, the patient (male, 48 years old) was diagnosed with Gilbert's syndrome, chronic rhinosinusopharyngitis, and chronic herpesvirus infection. In July 2017, parvovirus B19 DNA was detected in blood. No clinical manifestations of infectious erythema were noted. The patient was admitted to the medical center of St. Petersburg Pasteur Institute. His blood samples obtained under informed consent were examined at the medical center in Central Clinical and Diagnostic Laboratory of St. Petersburg Pasteur Institute in January and June 2018 and in November 2019. ELISA test systems “Anti-Parvovirus B19 ELISA (IgM)” and “Anti-Parvovirus B19 ELISA (IgG)” (Euroimmune, Germany), as well PCR reagent kit “AmpliSens Parvovirus B19-FL” (FSB Central Research Institute of Epidemiology of Rospotrebnadzor, Russia) were used for specific diagnostics. Interferon status was determined by the induced production of IFN types I, II and circulating (serum) interferons. Moreover, we considered the laboratory data obtained earlier at different medical facilities of St. Petersburg. IgM class antibodies to the parvovirus B19 were not detected in the blood samples obtained in 2018. IgG antibody titer was 96 IU/ml and 264 IU /ml, respectively. Parvovirus B19 DNA was isolated from blood plasma, but the viral load was less than 720 IU of PVB19 DNA/ml (1.5 x 102 and 1.9 x 102 copies of DNA/ml, respectively). Clinical blood analysis, showed only minor (no more than 7%) deviations from the reference values, increased hemoglobin saturation of red blood cells (RBC), a decreased width of RBC distribution curve, and relative lymphocytosis. A deficiency of various interferon types was revealed: IFNγ level was 80 IU/ml in both samples, IFNα, IFNβ amounts varied from 80 to 160 IU/ml, respectively. The period of parvovirus B19 DNA persistence in blood was 11 months in presence of immunodeficiency. The patient was administered drugs of the interferon group. Parvovirus B19 DNA was not detected in clinical samples of November 2019; IFNα, IFNβ and IFNγ values were 160 IU/ml. We have detected recovery of lymphoid cell ratio, increase in their number, and improved indexes of interferon status.

Herd immunity to SARS-CoV-2 in the Novosibirsk Region population amid the COVID-19 pandemic

Aim. To determine the level of SARS-CoV-2 seroprevalence among the Novosibirsk Region population against the background of the COVID-19 pandemic.Material and methods. The work was carried out in 2 phases: 1) a cross-sectional cohort study performed 28.06– 15.07.2020; 2) longitudinal cohort 3-stage seromonitoring: 1st stage 28.06–15.07.2020; 2nd 14.09–04.10.2020; 3rd 10–30.12.2020 The work was carried out according to a unified methodology developed by Rospotrebnadzor with the participation of St-Petersburg Pasteur Institute, taking into account the recommendations of the WHO. IgG antibodies to the SARS-CoV-2 nucleocapsid protein were detected by ELISA using a kit of reagents produced by the SRCMSB (Obolensk) according to the manufacturer’s instructions. Statistical analysis was performed using Microsoft Excel 2010 and other programs.Results. The seroprevalence in the region’s population was 9.1% (95% CI 8.0–10.2): maximum in children 14–17 years old (17.6%, 95% CI 12.3–23.9) and persons over 75 years (14.8%, 95% CI 11.4–18.8), minimum among persons 30–39 years old (4.9%, 95% CI 3.0–8.0). Increased rate was noted among the unemployed (15.4%, 95% CI 9.9–17.1) and other individuals (13.0%, 95% CI 8.6–18.5). Seroprevalence was 33.3% (95% CI 16.3–59.0) in COVID-19 convalescents and 19.0% (95% CI 13.9-25.0) in contact persons. More than 94.7% (95% CI 91.2–97.2) of seropositive individuals were asymptomatic. During the serological monitoring, seroprevalence increased from 7.4% (95% CI 6.2–8.9) at 1st stage 1 to 12.4% (95% CI 10.6–14.3) at 2nd , and 31% (95% CI 28.8–33.3) at 3rd stage.Conclusion. SARS-CoV-2 herd immunity has not reached the threshold level, this does not exclude exacerbation of the epidemic process.

HISTORY OF JULES BORDEAUX IDEAS (dedicated to 150 anniversary of the birth of a scientist)

The experimental period in the history of immunology as a science can be attributed to the years of scientific activity of the world-famous bacteriologist and immunologist Jules Bordeaux, who was the first to experimentally prove the physicochemical nature of such immune reactions as agglutination, hemolysis, precipitation. He was also involved in revealing the nature of phagocytosis reactions and established the relationship between the virulence of the microorganism and the presence of a capsule and phagocytosis. Owing to the discovery of Jules Bordeaux, mankind became aware of the cytotoxic properties of blood serum. Bordeaux’s scientific heritage was the elucidation of the role of complement in immunological processes, which was proved experimentally during the work of a young scientist at the Pasteur Institute in the laboratory of I. I Mechnikov, who considered J. Bordeaux one of his favorite students. In collaboration with Octave Zhangou, the complement fixation reaction underlying Wasserman’s reaction was first proposed. Bordeaux is well known around the world for the «driving force» of immunity — the connection of antigen to antibody. He can be regarded as one of the founders of the method of serodiagnosis. Bordeaux was the director of the Pasteur Institute in Brussels for 35 years, the world’s only autonomous Pasteur Institute unrelated to Paris. Jules Bordeaux’s scientific legacy continued and became the basis for many epoch-making discoveries in medicine, including the explanation of the mechanisms of anaphylaxis, the study of blood clotting, the discovery of blood groups, etc. The theoretical substantiation of immunological reactions became the beginning of a new diagnostic direction in laboratory practice — immunoassay, which includes thousands of modern laboratory methods

Nasopharyngeal Samples Management Strategy During the COVID-19 Pandemic: Experience of the Pasteur Institute of Côte d'Ivoire (2020)

Medical testing laboratories are an essential link in the efficient management of infectious diseases by the identification of the pathogens involved. However, the arrangements for their operation may appear more difficult in times of health crises and raise multiple issues that may compromise the usual level of quality assurance of biological analyses and the response to needs. The smooth running and control of laboratory activities in a health crisis situation requires the implementation of a management system that allows the federation of all available energies. We report here on the experience of the Pasteur Institute of Côte d'Ivoire, in charge of nasopharyngeal samples management during the COVID 19 pandemic, describing the assessment of pre-analytical activities in the first quarter of the crisis (March to May 2020). We then present the implemented strategy and the results obtained from June to September 2020. This article proposes a framework for sharing experiences to contribute to a better preparation of the pre-analytical phase of laboratory samples during health crises.

Synbiotics in oral immunity: a review

<p class="abstract">The oral cavity harbors numerous and varied microbial flora. The existence of probiotics in the indigenous oral micro flora of humans warrants exploration because these bacteria offer the advantage of being perfectly adapted to the oral ecosystem. The concept of probiotics probably dates back to 1908 when the long life of Bulgarian peasants was the result of their lifelong consumption of fermented milk products. The pursuit of original observation of the positive role played by some selected bacteria, as investigated by Elie Metchnikoff, the Ukrainian-born Nobel Prize winner working at the Pasteur Institute, at the beginning of the last century much still remains to be done to standardize the meaning of the term synbiotic and which strains actually fulfil the criteria of true synbiotic microorganisms. Since, there are established reports in its applicability, this opens up a new era of interest.</p>