В декабре 2019 появилась информация о новом заболевании, этиологическим фактором которого оказался β-коронавирус SARS-CoV-2. В Ленинградской области первый случай COVID-19 выявлен 13 марта 2020 года. Период нарастания интенсивности эпидемического процесса продолжался 8 недель. Через один месяц после достижения максимального уровня заболеваемости было организовано исследование по определению серопревалентности к COVID-19 среди населения Ленинградской области. Работа проводилась в рамках проекта Роспотребнадзора по оценке популяционного иммунитета к вирусу SARS-CoV-2 у населения Российской Федерации с учетом протокола, рекомендованного ВОЗ. Содержание антител к SARS-CoV-2 определяли методом ИФА с использованием набора реагентов для анализа сыворотки или плазмы крови человека на наличие специфических иммуноглобулинов класса G к нуклеокапсиду вируса SARS-CoV-2 производства ФБУН ГНЦПМиБ Роспотребнадзора (г.Оболенск) в соответствии с инструкцией по применению. Результаты исследования показали, что коллективный иммунитет совокупного населения Ленинградской области составил 20,7%. Максимальный уровень коллективного иммунитета установлен у детей 1-6 лет (42,3%) и обследованных старше 70 лет (29,0%). Наибольший уровень серопозитивности, кроме детей и лиц старшего возраста, выявлен у безработных (25,1%). Наименьший уровень серопревалентности установлен в подгруппе госслужащих (12,8%) и подгруппе военных (16,7%). Показано, что при наличии контактов с больными COVID-19 риск инфицирования возрастает в 1,5 раза. После инфекции COVID-19 антитела вырабатываются в 82,1% случаев. У лиц с позитивным результатом ПЦР-анализа, полученным ранее, антитела выявляются в 82,8% случаев. Доля бессимптомных форм среди серопозитивных жителей Ленинградской области составила 86,9%. Результаты оценки популяционного иммунитета к вирусу SARS-CoV-2 у населения Ленинградской области свидетельствуют о том, что в период эпидемического подъема заболеваемости инфекцией COVID-19 сформировался средний уровень серопревалентности. После перенесенного заболевания у 18% лиц, антитела не выявляются. Значительная доля бессимптомных форм инфекции характеризует высокую интенсивность скрыто развивающегося эпидемического процесса. Полученные результаты необходимо учитывать при организации профилактических мероприятий, включая вакцинацию, и прогнозировании заболеваемости.
The first case of COVID-19 was registered in the Leningrad Region on March 13, 2020. The period of increasing intensity of the epidemic process lasted 8 weeks. One month after reaching the maximum incidence rate, a study was organized to determine seroprevalence to COVID-19 among the population of the Region.Objective of the study was to determine the level and structure of community immunity to SARS-CoV-2 virus in the population of the Leningrad Region in the period of intensive COVID-19 transmission.Materials and methods. The work was carried out within the framework of the Rospotrebnadzor project on assessment of community immunity to the SARS-CoV-2 virus in the population of the Russian Federation. The content of antibodies to SARS-CoV-2 was determined applying ELISA using a kit for the analysis of human serum or blood plasma for the presence of specific IgG to the nucleocapsid of the SARS-CoV-2 virus , manufactured by the State Scientific Center of Applied Microbiology and Biotechnology (Obolensk) in accordance with the instructions for use.Results and discussion. The study has showed that the herd immunity of the population of the Leningrad Region was 20.7 %. The maximum level has been established in children 1–6 years old (42.3 %) and people over 70 years old (29.0 %). The highest level of seropositivity, except for children and older people, was found among the unemployed (25.1 %). The lowest level of seroprevalence was detected in civil servants (12.8 %) and military personnel (16.7 %). It has been shown that the risk of infection increases by 1.5 times in case of contacts with COVID-19 patients. After exposure to COVID-19 virus, antibodies are produced in 82.1 % of the cases. In individuals with a positive PCR test result obtained earlier, antibodies are detected in 82.8 % of cases. The share of asymptomatic forms among seropositive residents of the Leningrad Region was 86.9 %. The results of assessing the herd immunity to SARS-CoV-2 in the population of the Leningrad Region indicate that during the period of intensive COVID-19 transmission, an average level of seroprevalence was formed. A significant proportion of asymptomatic forms of infection characterizes the high intensity of the latently developing epidemic process. The results obtained should be taken into account when organizing preventive measures, including vaccination, and predicting morbidity rates.
Introduction. To achieve the goal of eliminating viral hepatitis by 2030, it is necessary to assess the real situation, improve epidemiological surveillance and prevention of these infections. Objectives: To evaluate the results of epidemiological surveillance of chronic viral hepatitis B, C, D and hepatocellular carcinoma in order to optimize the surveillance system at the regional level. Materials and methods: We analyzed the incidence of viral hepatitis B, C and liver cancer in the regions of the Northwestern and Central Federal Districts of the Russian Federation over the past 10 years. We also studied the prevalence of hepatitis B, C, D, and hepatitis C virus genotypes (6,020 cases), and examined 465 case histories of patients with hepatocellular carcinoma in the Leningrad Region using techniques of epidemiological analysis, ELISA, PCR, and statistical methods. Results: We established a tendency towards a decrease in the incidence of chronic hepatitis B and C in all study areas. In 2020, high rates of hepatitis B (26.2 and 9.1) and hepatitis C (49.2 and 39.2) were registered in St. Petersburg and Moscow per 100,000 population, respectively. The prevalence of hepatitis D in the Leningrad Region was 6.3 per 100,000 population. Hepatitis C virus genotypes 1 and 3 prevailed (48.9 % and 43.9 %, respectively). A high incidence of liver cancer was established in St. Petersburg, the Pskov and Novgorod Regions. Conclusions: Our findings prove the efficiency of the surveillance system and prevention of chronic hepatitis B and C. The main objectives are to further reduce the incidence rate, screen all patients with chronic hepatitis B for hepatitis D, and use the results of molecular genetic studies and cancer registries for epidemiological surveillance purposes.
Introduction. Vaccination contributed to reduce the incidence of acute hepatitis B in the territories of the North-West Russia. The urgency of this problem remains due to the high incidence of chronic hepatitis B. This accounted for the need to develop a hepatitis B elimination program in the district discussed that was approved in 2013 by the head of the Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing. Objective is to characterize the results of the program for the elimination of acute hepatitis B virus implemented in the North-Western Federal District. Materials and methods. The 2010–2020 incidence rate of acute and chronic hepatitis B virus (HBV) infection in the regions of the North-West Russia was carried out. To determine HBV genotypes and subgenotypes, 160 blood plasma samples from patients with acute hepatitis B were studied using molecular genetic methods (PCR, sequencing). The prevalence of latent hepatitis B in various population groups was assessed. The 2016–2020 hepatitis B vaccination coverage and relevant serological monitoring in adults was carried out. Results. While implementing the program, it was found that the incidence rate of acute hepatitis B in the district decreased by 4.5-fold, revealing in 2020 no cases of the disease in 5 regions, with incidence rate in the 6 subfederal units being lower than 1.0 per 100,000 population. Moreover, the incidence rate for chronic hepatitis B decreased by 2.6 times. The 2020 vaccination coverage of children under 17 and adults in all territories comprised more than 95% and 90%, respectively. In addition, it was shown the circulation of genotypes D and A of hepatitis B virus is dominated by genotype D (91.8%), subgenotype D2 (47.8%). The prevalence of latent hepatitis B among migrants was 6.5%, pregnant women — 4.9%, hemodialysis patients — 1.7%. Conclusion. Implementation of the program on elimination of acute viral hepatitis B in the territory of the North-West Russia contributed to raise in the vaccination coverage in adult population and lowered incidence rate of acute and chronic HBV infection.
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