- health care worker (doctor, nurse, midwife, paramedic, laboratory diagnostician or other person having direct contact with a patient) in the age group >25 years, - no confirmed SARS-CoV-2 infection history, - informed consent to participate in the study and consent to the processing of personal data, - declared availability for telephone contact throughout the study period, - good state of health, - previously performed vaccination against tuberculosis,

- health care worker (doctor, nurse, midwife, paramedic, laboratory diagnostician or other person having direct contact with a patient) in the age group >25 years, - no confirmed SARS-CoV-2 infection history, - informed consent to participate in the study and consent to the processing of personal data, - declared availability for telephone contact throughout the study period, - good state of health, - previously performed vaccination against tuberculosis,