The coronavirus disease pandemic (COVID-19) was announced by WHO in February 2020. In Moscow, the first case of the disease was detected on March 2, 2020 in a man who arrived from Italy. Two weeks after the first case, there was an exponential increase in the number of cases. The incidence peaked in the 19th week of the year, followed by a steady decline, lasting 16 weeks. Objective. To investigate the level and structure of population immunity to the SARS-CoV-2 virus among the population of Moscow against the background of the incidence of COVID-19. Patients and methods. The study of population immunity of Moscow residents to SARS-CoV-2 was carried out in the period from July 1, 2020 to July 30, 2020 against the background of stabilization of the incidence rate. The work was conducted as part of the first stage of the Rospotrebnadzor project to assess population immunity to the SARS-CoV-2 virus among the population of the Russian Federation, taking into account the protocol recommended by WHO. Volunteers for the study were selected by the method of questioning and randomization. The results of the survey of 2688 people were included in the analysis. The number of volunteers in all age groups was 384–385 people. The content of specific IgG to the SARS-CoV-2 nucleocapsid was determined by the enzyme-linked immunosorbent assya using a kit produced by FBIS SRCAMB according to the manufacturer's instructions. Results. During the survey of volunteers it was found that the share of seroprevalent residents of Moscow was 22.1%. By age groups, the highest proportion of seroprevalent was found among children aged 14–17 years (44.6%), the lowest (15.9%) – among people aged 18–29 years. Seroprevalence had no gender differences. The lowest level of herd immunity was revealed in the North-Western Administrative District (16.8%), the highest – in the South-Eastern Administrative District, as well as in the Troitsky and Novomoskovsky Administrative Districts of Moscow (in both, 24.1%). The smallest number of seropositive persons was among cultural workers (5.8%), the largest – among medical workers (27.0%). In the presence of contacts with patients with COVID-19, the probability of seroconversion increases by 1.5 times, and among convalescing persons COVID-19 antibodies were detected in 60.0% of cases. The proportion of people with asymptomatic infection among seropositive residents was 82.4%. Conclusion. The results obtained make it possible to characterize the population immunity of Moscow residents and are essential for the planning and implementation of anti-epidemic measures during the incidence of COVID-19. Key words: coronaviruses, SARS-CoV-2, seroprevalence, population, COVID-19
Background. Nosocomial transmission of HBV and HCV is often believed to be associated with transfusion of inapparent infection blood. Nevertheless, recently both promotion of voluntary (fee free) donorship and the evolution of laboratory screening, including the introduction of high-sensitivity tests, have significantly reduced the transfusion-associated complications, including infectious ones. The incidence ratae of primary transfusion-transmitted infections in patients with hematological malignancies remains to be high. A lot of publications are devoted to epidemiological studies on the determination of the source of infection with parenteral viral hepatitis by virtue of molecular analysis of viral strains, which is one of the important tools for obtaining objective data on the presence or absence of epidemiological relationship in the investigation of iatrogenic cases of infection. However, there is still no clear algorithm for pursuing epidemiological investigations of such cases. The aim of this study was to develop the procedure for the epidemiological investigation of probable transfusion-transmitted HBV and HCV infection with the use of Laboratory Information System and Transfusiology Information System software in patients with hematological malignancies. Material and methods. 6 cases of primary HBV and 3 cases of primary HCV were registered in patients with hematological malignancies in the National Medical Research Center for Hematology. All patients had a history of blood transfusions. A two-steps procedure for the epidemiological investigation was developed. 5 epidemiological investigations were held according to this procedure. 35 archival blood samples (7 from patients and 28 from blood donors) were tested for serological and/or molecular markers of HBV and HCV to fulfill this. Results. First step of procedure includes the determination of the date of initial infection (IID). IID is an earliest point of maximal likelihood of the detection of viral markers by laboratory techniques. This value is calculated on the basis of the results of a comprehensive virological examination of the recipient. The second step includes a history of blood transfusions from IID up to date of initial detection of primary infection evaluation. Then the analysis of donor-recipient pairs should be executed for the detection of probable sources of infection. As the result of study 5 epidemiological investigations were held in accordance to the developed procedure and the Laboratory Information System and Transfusiology Information System software. Two of the five investigations cannot be completed because of donors’ rejection to undergo a follow-up examination. In other cases infection transmission through the blood transfusion was excluded. Conclusion. A standard operating procedure of epidemiological investigation of HBV or HCV transmission has been developed and implemented. In order to reveal the latent forms of these infections a protocol of viral screening in patients with hematological malignancies at the admission to hematology ward was also developed and implemented.
In the last 5-7 years, the detection rate of markers of HBV infection in the blood samples of patients with blood system diseases have remained at a high level. Screening for decreed markers fails to identify people with inapparent infections among the donors. Even high anti-HBs concentrations in the donated blood may be a risk for HBV transmission by transfusion to a recipient.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.