The Incidence of a New Coronavirus Infection in Medical Workers and the Evaluation of the Effectiveness of Individual Technologies for their Protection at Different Stages of the Pandemic

Relevance. The study of the incidence of medical workers with a new coronavirus infection during the COVID-19 pandemic is one of the topical areas of epidemiological research at this stage. The search for effective practices to reduce the incidence and risk of SARS-CoV-2 spread among employees of medical organizations is a promising area of research that is in demand in practice. Аim. Analysis of COVID-19 morbidity among health care staff during the pandemic and determination of the significance of selected specific and nonspecific prophylaxis measures in minimizing the risk of their occupational infection with SARS-CoV-2. Materials and methods. The reporting forms «General information about patients with positive COVID-19», «General information about patients with community-acquired pneumonia with positive COVID-19» (497 units of information), 2 176 cards of epidemiological investigation of cases of COVID-19 among employees of three municipalities were analyzed. We used epidemiological and statistical research methods. Conclusions. When analyzing the incidence of COVID-19 among employees of the medical worckers of the Khanty-Mansi autonomous оkrug – Yugra in the period from the 19th calendar week of 2020 to the 36th week of 2021, which corresponded to three epidemic rises, it was found that its level exceeded such in the unorganized adult population by 2.2 times, as well as the frequency of severe clinical forms of infection with lung damage. In the first two epidemic rises in the incidence, the highest incidence rate was recorded when the chances (OR) of getting COVID-19 among workers in the medical organizations compared to the adult population were the highest. In the first «wave» of the pandemic, they were 3.0, and in the second 2.6 times higher, as were the chances of developing clinical forms of COVID-19 with lung damage, which differed by 2.2 and 1.7 times, respectively, from those of an adult population (p<0.05). During the third epidemic rise, the situation changed radically. The incidence of new coronavirus infection in ,medical worckers as well as the chances of getting sick, were equal to those in the adult population (OR 1.1), while the frequency of clinical forms of infection with lung involvement was even lower than in the population (P=95.7‰). The reason for the positive changes in the dynamics of the epidemic process was due to the formation among medical workers of a higher stratum of people protected from infection due to active, emergency vaccination and people with post-infection immunity as a result of infection in its various clinical forms than in the population. A detailed analysis of the incidence of COVID-19 in three medical organizations of Khanty-Mansiysk autonomous okrug - Yugra made it possible to obtain information that among employees of medical organizations vaccinated against a new coronavirus infection, the incidence of COVID-19 was 4.4 times lower than among those who were not vaccinated. In the cohort of those vaccinated, the frequency of clinical forms of the disease complicated by pneumonia was 4.7 times less, and the number of those hospitalized for inpatient treatment was 20.8 times lower. In medical workers who received a booster dose of the drug after vaccination, the incidence was 5.8 times lower compared to the unvaccinated cohort. Compared with the unvaccinated, there were 12.8 times fewer complicated clinical forms of the disease and 6.25 times the number of hospitalizations among them. A correlation was also found between the incidence of COVID-19 among employees of the medical workers and the area of premises per employee. Increasing the area of the premises per employee per 1 sq. m. led to a decrease in incidence by 2.1%.

1. Medvedev D. Six lessons from one pandemic. Russian newspaper.2021;(8600):1,4–5 (In Russ.).

2. Xiang B., Li P., Yang X., Zhong S., et al. The impact of novel coronavirus SARS-CoV-2 among healthcare workers in hospitals: an aerial overview. Am J Infect Control. 2020;(48):915–17. DOI: 10.1016/j.ajic.2020.05.020.

3. Nguyen LH, Drew DA, Joshi AD, et al. Risk of COVID-19 among frontline healthcare workers and the general community: a prospective cohort study. Lancet Public Health. 2020;5:475–83. DOI: 10.1101/2020.04.29.20084111.

4. Perez-Garcia F., Perez-Zapata A., Arcos N., et al. Severe acute respiratory coronavirus virus 2 (SARS-CoV-2) infection among hospital workers in a severely affected institution in Madrid, Spain: A surveillance cross-sectional study. Infection control and Hospital Epidemiology. 2020; 1–7. DOI:10.1017/ice.2020.1303.

5. Briko NI, Kagramanyan IN, Nikiforov VV, et al. Pandemic COVID-19. Prevention measures in the Russian Federation. Epidemiology and Vaccinal Prevention. 2020;19(2):4– 12 (In Russ). DOI: 10.31631/2073-3046-2020-19-2-4-12.

6. Akimkin VG, Kuzin SN, Semenenko TA, et al. Characteristics of the epidemiological situation in the Russian Federation in 2020. Annals of the Russian Academy of medical sciences. 2021;76(4):412–422 (In Russ). https://doi.org/10.15690/vramn1505.

7. Kutyrev V.V., Popova A.Yu., Smolensky V.Yu., et al. Epidemiological peculiarities of New Coronavirus Infection (COVID-2019). Communication 2: Peculiarities of epidemic process development in conjunction with performed anti-epidemic measures around the world and in the Russian Federation. Problemy Osobo Opasnykh Infektsii [Problems of Particularly Dangerous Infections]. 2020;2:6–12 (In Russ). DOI: 10.21055/0370-1069-2020-2-6-1.

8. Briko NI, Feldblyum IV. The Modern Concept of Development of Vaccine Prevention in Russia. Epidemiology and Vaccinal Prevention. 2019;18(5):4–13 (In Russ.). https://doi:10.31631/2073-3046-2019-18-5-4-13.

9. Angel Y., Spitzer A., Henig O., et al. Association between vaccination with BNT162b2 and incidence of symptomatic and asymptomatic SARS-CoV-2 infections among health care workers. JAMA. 2021 Jun;325(24):2457-2465. DOI: 10.1001/jama.2021.7152.

10. Hall V., Foulkes S., Saei A., et al. COVID-19 vaccine coverage in health-care workers in England and effectiveness of BNT162b2 mRNA vaccine against infection (SIREN): a prospective, multicentre, cohort study. Lancet. 2021 May 8;397(10286):1725–1735. DOI: 10/1016/S0140-6736(21)00790-X.

11. Sisin EI., Golubkova AA. Kozlova II., Ostapenko NA. Epidemiological risks and lessons from the first wave of new coronavirus infection (COVID-19) in healthcare organizations. Epidemiology and infectious diseases. 2020;25(4):156–166 (In Russ.). DOI: 10.17816/EID54401.

12. Logunov DY, Dolzhikova IV, Zubkova OV, et al. Safety and immunogenicity of an rAd26 and rAd5 vector-based heterologous prime-boost COVID-19 vaccine in two formulations: two open, non-randomised phase 1/2 studies from Russia. Lancet. 2020 Sep 26;396(10255):887–897. doi: 10.1016/ S0140-6736(20)31866-3.

13. Logunov DY, Dolzhikova IV, Shcheblyakov DV, et al. Gam-COVID-Vac Vaccine Trial Group. Safety and efficacy of an rAd26 and rAd5 vector-based heterologous prime-boost COVID-19 vaccine: an interim analysis of a randomised controlled phase 3 trial in Russia. Lancet. 2021 Feb 20;397(10275):671–681. doi: 10.1016/S0140-6736(21)00234-8.

14. Kharchenko E.P. Vaccines against Covid-19: the Comparative Estimates of Risks in Adenovirus Vectors. Epidemiology and Vaccinal Prevention. 2020;19(5):4–17 (In Russ.). https://doi.org/10.31631/2073-3046-2020-19-5-4-17.

15. Ryzhikov A.B., Ryzhikov Е.А., Bogryantseva M.P., et al. A single blind, placebo-controlled randomized study of the safety, reactogenicity and immunogenicity of the «EpiVacCorona» Vaccine for the prevention of COVID-19, in volunteers aged 18–60 years (phase I–II). Journal of Infection and Immunity. 2021;11(2):283–296 (In Russ.). https://doi.org/10.15789/2220-7619-ASB-1699.