The ongoing COVID-19 pandemic around the world and in Russia remains a major event of 2020. All over the world, research is being conducted to comprehensively study the patterns and manifestations of the epidemic  process. The main quantitative characteristics of SARS-CoV-2 transmission dynamics among the population, based on the data of official monitoring over the current situation, play an important role in the development of  the epidemiological surveillance system.The aim of this study is to explore the peculiarities of age-gender distribution of COVID-19 patients in Moscow.Material and methods. The data related to the epidemiological characteristics of age-gender structure of COVID-19 patients in Moscow between March 19, 2020 and April 15, 2020, at different stages of the  epidemic were retrospectively analyzed.Results and discussion. The mean age of COVID-19 patients in Moscow was 46,41±20,58 years. The gender ratio (male/female) among the patients was 52.7/47.3 %, wherein the indicators varied depending upon the  age. Male/female ratio in the age group “under 39” stood at 53.7/46.3 %, and “over 40 years of age” – at  39.3/60.7 %. The predominant age range among male cases was 19 to 39 years old – 35.4 %, while among female patients – 40–59 years (36.5 %). The age distribution of patients in Moscow is indicative of the fact that COVID-19 is a disease that primarily affects older age groups. The age structure of all COVID-19 cases during the observation period is characterized by predominance of adult patients over 19 years of age – 92,7 % (92,6–92,8 %), the share of patients aged 40–59 years is 35,7% (35,5–35,9 %). The differences in the age distribution in males and females are as follows: in the male cohort, the age groups 19–39 years old and 40–59 years old prevail – 35.4 % (35.1–35.7 %) and 34.9 % (34.6–35.2 %), respectively. The age group 40–59 years old – 36.5 % (36.3–36.8%) dominates in the female cohort.

We studied individual parameters of the COVID-19 epidemic process in the Nizhny Novgorod region for the period from February 26 to July 22, 2020. It was shown that the most intensively involved in the epidemic process were persons of the age category from 42 to 65 years, among the sick the proportion of women was more (58,12%) than the proportion of men (41,8%). A positive correlation was found between the number of COVID-19 cases and age for the age groups from 19 to 41 years old and from 42 to 65 years old.

We studied individual parameters of the COVID-19 epidemic process in the Krasnodar Territory for the period from March 10 to August 17, 2020. It is shown that a high level of morbidity remains after the abolition of restrictive measures — on average, 83 patients with COVID-19 were registered per day in the final phase of the observation period. The proportion of patients with severe and moderate disease is 63.7%, and in persons over the age of 65, their proportion is slightly higher — 76.0%. The most intensively involved in the epidemic process are pensioners, temporarily unemployed (men and women) and workers of medical organizations (women).

We studied the epidemiological situation of the COVID-19 epidemic in the Stavropol Territory during March 19 2020 to Аugust 12, 2020. There was no significant decrease in the number of new cases after the phase of the increased incidence of COVID-19. The average number of registered COVID-19 patients in the final phase of the observation period was 93 per day. It has been shown that the frequency of severe forms of COVID-19 is higher in patients of older age groups: in the group of 80 years and older, the frequency of moderate and severe forms of COVID-19 was 69.4%, while in the group under 27 years old — 23.6%. A positive correlation was found between the number of COVID-19 cases and age for the age groups 20–41, 54–60 and 77–83 years (women) and 21–36 and 57–59 years old (men).

The review provides information on single nucleotide polymorphisms (SNPs) in genes encoding some interleukins belonging to the interleukin-1 (IL-1) superfamily and on their association with different infectious and non-infectious human diseases. It also briefs on the history of SNP discovery and the progress in the related scientific studies till the present time. It gives an insight into some mechanisms of interaction between infectious agents and the human immune system, involving SNPs in some cytokines of the IL-1 superfamily. The review provides data on relationships of SNPs in genes encoding other factors of the immune system, which are associated with the specific characteristics of natural history of chronic hepatitis B and C. It explores the significance of assessment of the SNP-proportion in proinflammatory cytokines and their antagonists of the IL-1 superfamily among the healthy population as well as the ratio of individual SNPs in specific groups of patients as a monitoring parameter for epidemiological surveillance of infectious diseases.