Epidemiological Study of the COVID-2019 in Participating Organizations.

Exhaustive, cross-sectional, non-interventional, multicenter retrospective epidemiological study, case study aimed to determine the relationship between the systematic use of prophylactics to prevent SARS, including COVID-2019, and the risks of incidence and serious complications of COVID-2019 among staff of participating organizations.

Coronaviruses are a large family of viruses that might cause illness in animals or humans. SARS-CoV-2 is an enveloped, single-stranded RNA virus of the β genus. It can cause respiratory illness named COVID-19, the severity of which varies from asymptomatic to severe, and which can lead to the patient's death of the long-term consequences (so-called post-COVID syndrome). The virus has spread globally and been declared a Public Health Emergency of International Concern by WHO in January 30, 2020.

The first case of COVID-19 in Ukraine was detected in early March, 2020. 1273475 cases of the disease have been registered in Ukraine as at February 15, 2021.

Quarantine restrictions and other anti-epidemic measures established in Ukraine and their results are the subject of wide debate.

Own anti-epidemic measures, in addition to those established by the Government, have also been implemented by numerous representatives of the public sector, non-governmental organizations and business.

The company management of the participating organizations decided to provide their staff with prophylactic tools and recommendations for COVID-19 prevention.

The study aims to identify the incidence, characteristics of cases and their relationship with the preventive measures used.

Each subject will be assigned an individual number, which will be used for conduction of a rapid ELISA test for the antibodies to COVID-2019. Subjects will be notified of the test results.

The questionnaires will be conducted when the subject enters the data in the electronic case report form after signing the consent to processing of personal data.

For the purposes of analysis, the subject enters his individual number in the questionnaire, as well as number of a rapid ELISA test for antibodies to COVID-2019 and its result. The entered data will be compared with the databases which contain the results of rapid ELISA tests.

The questionnaire includes questions related to the main risks and protective factors of the COVID-2019 disease: demographic, anthropometric data, lifestyle data, prophylactics methods, subject's costs spent on COVID-2019 prophylactics.

For subjects who had the COVID-2019 case, a separate block of questionnaire was created to collect data on prophylactics, treatment of COVID-2019, the course of the disease and the consequences of the disease case, as well as costs spent on COVID-2019 treatment.

The completeness of entered data in the electronic case report form will be controlled by specially designated authorized persons in each participating organization, who were designated by the person responsible for conducting the study in each participating organization.

The correctness of entered data in the electronic case report form will be controlled by remote monitoring.

The questionnaire cannot be completed until all required fields of the case report form have been completed.

A structured description of the available medical documentation for fatal cases of COVID-2019 will be conducted separately.

Demographic, anthropometric data, lifestyle data, prophylactics methods, treatment of COVID-2019, the course of the COVID-2019 case will be described.

Calculation of sample size is not applicable as it is exhaustive study. Participating organizations undertake to organize the involvement in the study of at least 95% of persons employed by participating organizations.

In the context of this data analysis, all the main steps from the primary data to the results of the study will be described separately in the Statistical Analysis Plan.

This study is not intended to accept or reject pre-defined hypotheses, thus statistical analysis will mainly be descriptive.

All types of analysis will be done for the entire available study population with available data.

If there is a sufficient amount of data in the subpopulations, a separate statistical analysis will be performed.

No conditional calculation methods will be applied to the missed values. The statistical generalization will consist of frequency tables of categorical variables (number, %).

For metric variables, descriptive statistics (number of subjects with available observations, number of missed values, mean, standard deviation, median, 25th and 75th percentiles, minimum and maximum) will be presented in tabular form.

Statistical conclusions will be used to assess the potential relationship between the identified variables and the incidence / severity of COVID-2019.

The relationship between the subject's characteristics and the variables of interest will be assessed using a one-dimensional and multidimensional (polynomial) logistic regression model for variables, which have no more than 20% omitted data.

The final model will be selected with a view to minimizing the Akaike information criterion value.

2×2 tables, χ-square were used for calculations of odds ratios. Rough odds ratios and adjusted odds ratios with corresponding 95% confidence intervals and p-values will be generated and presented for both one-dimensional and multidimensional logistics models.

Eligibility Criteria:
Inclusion Criteria:

1. The subject gave the consent to participate in the study and signed the consent to processing of personal data.
2. The subject aged 18 years and older.
3. The subject is employed by one of the participating organizations.

Exclusion Criteria:

The subject may not be included in the study due to non-compliance with the inclusion criteria or due to force majeure.