A Study to Confirm the Effectiveness and Safety of AK0529 in Treating RSV Infections in Hospitalized Infants

Main Inclusion criteria: 1. Male or female subjects of any ethnicity with an age adjusted for any prematurity of ≥1 month and ≤24 months. 2. Diagnosis of RSV infection by any virological means, including a rapid diagnostic point-of-care testing, within 36 hours preceding initial dosing. 3. The onset of RSV infection symptoms should be ≤ 5 days prior to initial dosing. 4. Subject must weigh ≥ 2.5 kg and ≤ 20 kg at screening and be within the normal range for the subject's age, based on local child growth standards. 5. Subject must have a Wang bronchiolitis clinical score ≥ 5. Main Exclusion criteria: 1. The subject has taken any restricted medications within 3 days prior to the date of screening or requires any restricted medications during treatment phase (including interferons, ribavirin, or proprietary Chinese medicines with antiviral effects) and has taken any inhaled or systemic glucocorticoids within 24 hours. 2. Subject is known to have co-infection with influenza virus, Mycoplasma, or other respiratory tract pathogens that require targeted clinical treatment . 3. Subject is known to have bacterial pneumonia. 4. Subject with clinical evidence of hepatic decompensation (e.g., liver disease with coagulation abnormalities or encephalopathy). 5. Subject with inborn symptoms of metabolic abnormalities (e.g., mitochondrial diseases, carbohydrate metabolism abnormalities, glycogen accumulation diseases). 6. Subject with chronic or persistent feeding difficulties. 7. The parent or guardian of the subject is an employee of the study investigator or the study facility (such person will be directly involved in the study or any other study administered by the study facility investigator), or a family member of the study investigator or his/her staff. 8. Subject who have participated in clinical trials of other drugs or devices in the 30 days prior to screening. 9. Subject with any other reason that the investigator deems unsuitable for participation in the study.