The main purpose of this study is to evaluate the effectiveness of the prophylactic use of Ingaron (INN: recombinant interferon gamma human, lyophilisate for solution for intranasal administration 100,000 IU) in the regimen of 3 drops in each nasal passage intranasally every other day for 10 days with a break of 7 days (2 10-day cycles) in volunteers.

Distribution between groups is made randomly at the request of the participant. According to the methodology approved by the observational program, the participant must use or not use the investigational drug (depending on the distribution group and their own will) during the 27 days of the prophylaxis course (10 days + 7 days + 10 days). The control group does not receive study therapy.

Inclusion Criteria:

1. Medical workers and medical personnel working in the "red zone" and in contact with patients infected with COVID-19.
2. Men and women over 18 years of age.
3. Signing an informed consent form for data processing.
4. Ability and agreement to complete the questionnaire (part 1) of the participant.
5. No symptoms of a respiratory infection.
6. Negative PCR test result for the presence of SARS-CoV-2 RNA according to the biomaterial obtained by nasopharyngeal swab.

Exclusion Criteria:

1. Any clinically confirmed or documented history of diseases that may complicate the interpretation of the data being assessed (HIV, cancer, organ transplantation, etc.).
2. Any other comorbidities or conditions that, in the opinion of the investigator, may distort the results of the study, limit the rights of the volunteer, or put him at greater risk.
3. Contraindications to the use of the investigational medicinal product.
4. Individual intolerance to the ingredients that make up the study drug.
5. Pregnancy or breastfeeding.
6. The presence of antibodies to SARS-CoV-2 (IgM, IgG).

Volunteers working in the "red zone" with patients infected with SARS-CoV-2