The hygienic assessment on the level of actual contamination of air by microorganisms is carried out. Microbiological method established a wide species diversity of bacteria, yeasts and fungi in the air of the working area. The high informativeness of the assessment of the biological factor of working conditions of medical workers on the level of actual contamination of air by microorganisms of premises is determined.

In late 2019, there were reports of an outbreak of infection caused by a new strain of beta coronavirus SARSCoV-2, the WHO identified the disease as coronavirus disease 2019 (COVID-19). In Tatarstan, the first case of COVID-19 was diagnosed on March 16, 2020, it was an imported case from France. The period of increase in the incidence lasted during the 12th to the 19th week, when the highest rate was recorded, amounting to 16.7 per 100 thousand population. Subsequently, a statistically significant decrease in the incidence was noted. Seroprevalence study was conducted at week 27 (8th week of decline of morbidity).The purpose of the seroepidemiological study was to measure the level and to identify the structure of herd immunity against the SARS-CoV-2 virus among the population of the Republic of Tatarstan during the rapid spread of the COVID-19 outbreak.Materials and methods. The selection of volunteers for the study was carried out by the method of questionnaires and randomization by random sampling. The exclusion criterion was active COVID-19 infection at the time of the survey. 2,946 people were examined for the presence of specific antibodies to SARS-CoV-2. The age of the surveyed volunteers ranged from 1 year to 70 years and older.Results. The results of the study showed that in the Republic of Tatarstan during the period of COVID-19 incidence, there was a moderate seroprevalence to SARS-CoV-2, which amounted to 31.3%, against the background of a high frequency (94.5%) of asymptomatic infection in seropositive individuals who did not have a history of past COVID-19 disease, positive PCR result and ARVI symptoms on the day of the examination. The maximum indicators of herd immunity were established in children aged 7–13 years (42.0%), children 14–17 years old (40.3%), with a simultaneous decrease in seroprevalence in persons aged 70 and older (24.0%). In different regions of the Republic of Tatarstan, there was a wide variation in seropositivity results from the minimum in the Zainsky district (8.6%) to the maximum in the Arsky district (74.3%). In 21 out of 38 surveyed districts, the results were unrepresentative due to the small sample size. In COVID-19 convalescents, antibodies are produced in 83.3% of cases. In persons with a positive result of the PCR analysis carried out earlier, antibodies were detected in 100% of cases. Among the volunteers who had contact with patients with COVID-19, the proportion of seropositive is 37%Conclusion. The dynamics of seroprevalence among the population of the Republic of Tatarstan can be qualified as positive, the results obtained can be used to develop a forecast for the development of the epidemiological situation, as well as to plan measures for specific and non-specific prevention of COVID-19.

Aim. Investigation of the features of epidemiological characteristics of infectious morbidity associated with medical care registered in newborns in maternity care facilities of the Republic of Tatarstan. Methods. Retrospective epidemiological study of the morbidity of infections associated with medical care registered in newborns in the Republic of Tatarstan was performed. Epidemiological analysis was carried out using the forms of Federal statistical observation №2 of the Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing «The information about the infectious and parasitic diseases» (section «Hospital-acquired infections»). Results. Based on the received materials epidemiological analysis of the dynamics of hospital-acquired infectious morbidity in newborns for the period from 2009 to 2015 was performed. Unidirectional trend of infectious morbidity associated with medical care and of various nosological forms was revealed. Downward trend with a negative morbidity growth rate was identified for neonatal pneumonia, osteomyelitis, pyoderma, impetigo, mastitis, panaritium and paronychia of newborns, omphalitis, phlebitis of the umbilical vein and neonatal conjunctivitis. Neonatal morbidity of hospital-acquired otitis media did not changed from the baseline. Prevalent nosological forms of infections associated with medical care among newborns were pyoderma, impetigo, mastitis, panaritium, paronychia (33.6%) and pneumonia (29.5%). Conclusion. The average morbidity of infections associated with medical care in newborns in the Republic of Tatarstan for the period from 2009 to 2015 was 13.0 per 1000 newborns; negative dynamics of the morbidity with negative morbidity growth rate in newborns during this period was revealed (-42.3%).

The retrospective epidemiological study was carried out concerning infections related to medical care support registered in population on the territory of the Republic of Tatarstan in 2002-2015. The reason of such a study was because of late identification and registration of infections related to medical care support, significant damage to population health, development of complications in significant percentage of hospitalized patients and necessity of investigation of patterns of development and outspread of nosocomial infections. The epidemiological analysis was implemented using report form of the Federal statistical observation № 2 of the Federal service of control of sector of defense of rights of consumers and human well-being “The data of infectious and parasitic infections”. The dynamics, structure of many years morbidity and main parameters of manifestation of epidemic process were investigated. The derived data was used as a basis to provide epidemiological characteristic of many years' dynamics of various classes of infections related to medical care support. The indices of morbidity are calculated with consideration for average annual population size. The priority nosologic forms of infections related to medical care support were established concerning newborns (pyodermatitis, conjunctivitis, pneumonia, omphalitis, sepsis, etc.), puerpera (pyo-septic infections, mastitis, sepsis), adult population (postoperative and post-injection complications, infections of urinary tracts, nosocomial pneumonia, viral hepatitis, etc.) which dynamics was characterized by positive and negative rate of increment of indicator. The obtained data was compared with indices represented in national and foreign publications. The implemented study testifies the necessity of development of measures epidemiological monitoring of decreasing of morbidity because of infections related to medical care support in medical organizations.