Incidence of COVID-19 disease and the severity of SARS-CoV-2 infection and relationship with angiotensin II type 1 receptor (ATII-1R) concentration in healthcare professionals.

The cross-sectional observation study will be carried out on physicians and nurses (n=80) from the Wroclaw hospitals (Poland). The study has a voluntary charter and requires informed and written consent to participate. Two study groups will be identified. The first group (n=40) will include health care providers (physicians and nurses), who have so far had a negative result test of the real-time polymerase chain reaction (rt-PCR) for SARS-CoV-2 (control group). The second group (n=40) will include physicians and nurses who have undergone a COVID-19 infection with a confirmed rt-PCR test for SARS-CoV-2. On the day of the examination, 1 sample of blood (2.7 ml) will be taken to determine the ATII-1R concentration. After collection, blood samples will be left at room temperature to form a clot (about 30 minutes). They will then be centrifuged for 10 min with 3000 rpm. The resulting sera will be frozen and stored at -700C until the determination is performed. Demographic data, BMI, blood group, ATII-1R concentration will be analyzed. Additionally, information on chronic diseases (diabetes, hypertension, nicotinism, kidney failure) and medications will be collected. The results will be analyzed statistically. In the group of "recoveries", the symptoms of SARS-CoV-2 infection and the severity of COVID-19 will be additionally evaluated according to the illness categories described in Clinical Presentation of People with SARS-CoV-2 Infection based on the COVID-19 Treatment Guidelines developed by the National Institutes of Health (NIH): 1. Asymptomatic or Presymptomatic Infection: Individuals who test positive for SARS-CoV-2 using a virologic test (i.e., a nucleic acid amplification test or an antigen test) but who have no symptoms that are consistent with COVID-19. 2. Mild Illness: Individuals who have any of the various signs and symptoms of COVID-19 (e.g., fever, cough, sore throat, malaise, headache, muscle pain, nausea, vomiting, diarrhea, loss of taste and smell) but who do not have shortness of breath, dyspnea, or abnormal chest imaging. 3. Moderate Illness: Individuals who show lower respiratory disease evidence during clinical assessment or imaging and who have a saturation of oxygen (SpO2) equal to 94% on room air at sea level. 4. Severe Illness: Individuals who have SpO2 less than 94% on room air at sea level, a ratio of the arterial partial pressure of oxygen to fraction of inspired oxygen (PaO2/FiO2) less than 300 mmHg, respiratory frequency more than 30 breaths per minute or lung infiltrates more than 50%. 5. Critical Illness: Individuals who have respiratory failure, septic shock, and/or multiple organ dysfunction The approximate duration of the cross-sectional assessment would be 60-90 minutes.