inclusion criteria: 1. signed patient explanation sheet and informed consent for participation in the study. 2. men and women at the age from 18 through 75 years old. 3. history of acute coronavirus infection: * the patient has a history of confirmed diagnosis of covid-19 pneumonia, which resolved more than 2 weeks before screening; * history of covid-19 is confirmed by positive qualitative analysis of sars-cov-2 by polymerase chain reaction (pcr) or detection of sars-cov-2 antigens; * negative rapid test for sars-cov-2 antigen at screening and randomization; * onset of first symptoms of covid-19 from 42 to 120 days prior to randomization. 4. severity of mmrc dyspnea ≥2 at screening and randomization. 5. severity of exercise tolerance impairment at screening and randomization based on the 6-minute walk test: * reduction of the distance traveled below the normal limit (\< 80% of predicted) at the level of shortness of breath ≥2 units according to the borg scale; * severity of shortness of breath \> 2 units according to the borg scale, regardless of the presence of violations in the distance traveled. 6. the presence of foci of lung tissue seals such as "frosted glass" and/or interlobular septum seals, and/or areas of reticular changes in lung tissue, and/or the presence of areas (linear, focal) of lung tissue seals characteristic of covid-19 confirmed by chest ct at screening. the percentage of lung tissue damage is ≥10%, but \< 75% of the total lung volume. 7. the pulmonary diffusivity parameter is less than 80%, but more than 40% of predicted at the time of screening. 8. the patient's consent to use adequate contraception methods during the entire study and within 3 weeks after its completion. the adequate contraception methods include the use of the following: * oral or transdermal contraceptives; * condom or diaphragm (barrier method) with spermicide; * intrauterine device.

inclusion criteria: 1. signed patient explanation sheet and informed consent for participation in the study. 2. men and women at the age from 18 through 75 years old. 3. history of acute coronavirus infection: * the patient has a history of confirmed diagnosis of covid-19 pneumonia, which resolved more than 2 weeks before screening; * history of covid-19 is confirmed by positive qualitative analysis of sars-cov-2 by polymerase chain reaction (pcr) or detection of sars-cov-2 antigens; * negative rapid test for sars-cov-2 antigen at screening and randomization; * onset of first symptoms of covid-19 from 42 to 120 days prior to randomization. 4. severity of mmrc dyspnea ≥2 at screening and randomization. 5. severity of exercise tolerance impairment at screening and randomization based on the 6-minute walk test: * reduction of the distance traveled below the normal limit (\< 80% of predicted) at the level of shortness of breath ≥2 units according to the borg scale; * severity of shortness of breath \> 2 units according to the borg scale, regardless of the presence of violations in the distance traveled. 6. the presence of foci of lung tissue seals such as "frosted glass" and/or interlobular septum seals, and/or areas of reticular changes in lung tissue, and/or the presence of areas (linear, focal) of lung tissue seals characteristic of covid-19 confirmed by chest ct at screening. the percentage of lung tissue damage is ≥10%, but \< 75% of the total lung volume. 7. the pulmonary diffusivity parameter is less than 80%, but more than 40% of predicted at the time of screening. 8. the patient's consent to use adequate contraception methods during the entire study and within 3 weeks after its completion. the adequate contraception methods include the use of the following: * oral or transdermal contraceptives; * condom or diaphragm (barrier method) with spermicide; * intrauterine device.

inclusion criteria: signed patient explanation sheet and informed consent for participation in the study. men and women at the age from 18 through 75 years old. history of acute coronavirus infection: the patient has a history of confirmed diagnosis of covid-19 pneumonia, which resolved more than 2 weeks before screening; history of covid-19 is confirmed by positive qualitative analysis of sars-cov-2 by polymerase chain reaction (pcr) or detection of sars-cov-2 antigens; negative rapid test for sars-cov-2 antigen at screening and randomization; onset of first symptoms of covid-19 from 42 to 120 days prior to randomization. severity of mmrc dyspnea ≥2 at screening and randomization. severity of exercise tolerance impairment at screening and randomization based on the 6-minute walk test: reduction of the distance traveled below the normal limit (< 80% of predicted) at the level of shortness of breath ≥2 units according to the borg scale; severity of shortness of breath > 2 units according to the borg scale, regardless of the presence of violations in the distance traveled. the presence of foci of lung tissue seals such as "frosted glass" and/or interlobular septum seals, and/or areas of reticular changes in lung tissue, and/or the presence of areas (linear, focal) of lung tissue seals characteristic of covid-19 confirmed by chest ct at screening. the percentage of lung tissue damage is ≥10%, but < 75% of the total lung volume. the pulmonary diffusivity parameter is less than 80%, but more than 40% of predicted at the time of screening. the patient's consent to use adequate contraception methods during the entire study and within 3 weeks after its completion. the adequate contraception methods include the use of the following: oral or transdermal contraceptives; condom or diaphragm (barrier method) with spermicide; intrauterine device.

inclusion criteria: signed patient explanation sheet and informed consent for participation in the study. men and women at the age from 18 through 75 years old. history of acute coronavirus infection: the patient has a history of confirmed diagnosis of covid-19 pneumonia, which resolved more than 2 weeks before screening; history of covid-19 is confirmed by positive qualitative analysis of sars-cov-2 by polymerase chain reaction (pcr) or detection of sars-cov-2 antigens; negative rapid test for sars-cov-2 antigen at screening and randomization; onset of first symptoms of covid-19 from 42 to 120 days prior to randomization. severity of mmrc dyspnea ≥2 at screening and randomization. severity of exercise tolerance impairment at screening and randomization based on the 6-minute walk test: reduction of the distance traveled below the normal limit (< 80% of predicted) at the level of shortness of breath ≥2 units according to the borg scale; severity of shortness of breath > 2 units according to the borg scale, regardless of the presence of violations in the distance traveled. the presence of foci of lung tissue seals such as "frosted glass" and/or interlobular septum seals, and/or areas of reticular changes in lung tissue, and/or the presence of areas (linear, focal) of lung tissue seals characteristic of covid-19 confirmed by chest ct at screening. the percentage of lung tissue damage is ≥10%, but < 75% of the total lung volume. the pulmonary diffusivity parameter is less than 80%, but more than 40% of predicted at the time of screening. the patient's consent to use adequate contraception methods during the entire study and within 3 weeks after its completion. the adequate contraception methods include the use of the following: oral or transdermal contraceptives; condom or diaphragm (barrier method) with spermicide; intrauterine device.