[Modern views on the role of X gene of the hepatitis B virus (Hepadnaviridae: Orthohepadnavirus: Hepatitis B virus) in the pathogenesis of the infection it causes].

The review presents information on the role of hepatitis B virus (Hepadnaviridae: Orthohepadnavirus: Hepatitis B virus) (HBV) X gene and the protein it encodes (X protein) in the pathogenesis of viral hepatitis B. The evolution of HBV from primordial to the modern version of hepadnaviruses (Hepadnaviridae), is outlined as a process that began about 407 million years ago and continues to the present. The results of scientific works of foreign researchers on the variety of the influence of X protein on the infectious process and its role in the mechanisms of carcinogenesis are summarized. The differences in the effect of the X protein on the course of the disease in patients of different ethnic groups with regard to HBV genotypes are described. The significance of determining the genetic variability of X gene as a fundamental characteristic of the virus that has significance for the assessment of risks of hepatocellular carcinoma (HCC) spread among the population of the Russian Federation is discussed.

[Patterns of the SARS-CoV-2 epidemic spread in a megacity].

The purpose of the study is to analyze patterns demonstrated by the COVID-19 epidemic process in a megacity during the increase, stabilization and reduction in the incidence, and to evaluate the effectiveness of the epidemic prevention measures. MATERIALS AND METHODS: The comprehensive study incorporating epidemiological, molecular genetic and  statistical research methods was conducted to analyze the spread of SARS-CoV-2 in Moscow during the COVID- 19 pandemic. RESULTS AND DISCUSSION: It was found that the exponential growth in COVID-19 cases was prevented due to the most stringent control and restrictive measures deployed in Moscow to break the chains of SARS-CoV-2 transmission and due to people who were very disciplined in complying with the self-isolation rules. The  analysis of the dynamics in detection of new COVID-19 cases showed that in a megacity, the impact of social distancing and self-isolation would become apparent only after 3.5 incubation periods, where the maximum length of the period is 14 days. It was discovered that the detection frequency of SARS-CoV-2 RNA in relatively healthy population and its dynamics are important monitoring parameters, especially during the increase and stabilization in the COVID-19 incidence, and are instrumental in predicting the development of the epidemic situation within a range of 1-2 incubation periods (14-28 days). In Moscow, the case fatality rate was 1.73% over the observation period (6/3/2020-23/6/2020). CONCLUSION: The epidemiological analysis of the COVID-19 situation in Moscow showed certain patterns of the SARS-CoV-2 spread and helped evaluate the effectiveness of the epidemic prevention measures aimed at  breaking the routes of transmission of the pathogen.

[The panels of serums, containing various subtypes and mutant forms of HBsAg, to evaluate the diagnostics sensitivity of kits oa reagents detecting HBsAg].

The detection of HBsAg in blood serum using immune-enzyme analysis techniques decisively matters both for diagnostics of acute and chronic hepatitis B and screening of donor's blood and its components, controls of persons from risk groups of hepatitis B injection. The making of panels containing wide specter of samples of blood serums with sero-variants and mutant forms of surface antigen of hepatitis B virus widespread on the territory of the Russian Federation is necessary to control analytic and diagnostic sensitivity of test systems for detecting HBsAg. The testing of reagents kits to detect HBsAg using twi panels containing recombinant and native variants of HBsAg, demonstrated that these kits enable to detect various sero-vatriants of HBsAg (ayw2, adw2, ayw3varA, ayw3varB, adrq-) in concentration 0.1-0.01 IU/l and the so called elusive mutant forms of HBsAg of recombinant and native origin (G145R, Q129R, Q129H, Q129L, T143K, T126N, T126S, D144A, M133L, K141E and P142S). At that, the sensitivity can differ during the detection of native and recombinant mutant forms. The results testify the importance of using the panels both with recombinant and native samples containing the mutant forms of HBsAg in evaluation of sensitivity of reagents kits.

[Evaluation of the effect of mass vaccination against hepatitis B in the Russian Federation].

AIM: Evaluate the effect of mass vaccination against hepatitis B implemented within the framework of national project Health on the rate of development of unfavorable outcomes of infection and on average lifetime of the population of Russia. MATERIALS AND METHODS: Hepatitis B markers (HBsAg, anti-HBc, HBeAg, anti-HBe) were determined by enzyme immunoassayin 6211 blood serum samples from conditionally healthy population of 6 regions of the Russian Federation. Analysis of damage to health of the population caused by hepatitis B and favorable effect of mass vaccination against hepatitis B was performed by using mathematical model by Goldstein S.T. et al. (2005), that used results of detection of hepatitis B markers in discrete groups (women of childbearing age, children up to 5 years of age, adults aged 30 years and older). A formula developed by us was used to evaluate the effect of vaccination on the average lifespan of the population of the Russian Federation. RESULTS: The rate of HBsAg detection in the conditionally healthy population of the Tuva Republic was significantly higher (8.1%) than in other studied regions of the Russian Federation (p < 0.05): in Moscow Region--1.6%, in Rostov Region--1.6%, in Sverdlovsk Region--1.2%, Khabarosvk Region--2.0%, in Sakha (Yakutia) Republic--2.5%. The rate of detection of anti-HBc was significantly higher in the Tuva Republic and Sakha (Yakutia) Republic (46.2% and 42.3%, respectively); in other regions: Moscow Region--13.6%, Rostov Region--18.9%, Sverdlovsk Region--17.5%, Khabarovsk Region--21.0%. HBeAg in women of childbearing age was detected only in the Tuva Republic (0.4%). The mathematical analysis performed demonstrated that the level of coverage of vaccination of newborn children that in the studied regions is 96.1-99.6% may lead to the reduction of morbidity and mortality from hepatitis B and its outcomes by 91-95% that exceeds the similar parameter obtained by using our model, described in the literature for Africa, Asia and Europe. The calculated level of decrease of morbidity and mortality from hepatitis B and its outcomes may lead to the increase of average lifespan of the population of the Russian Federation by 1.44 - 4.08 months. CONCLUSION: The strategy of vaccination of newborn children against hepatitis B employed in the Russian Federation significantly reduces the risk of this disease and development of unfavorable outcomes of the disease especially in hyper endemic regions and promotes the increase of average lifespan of the population of Russia.