PhaseⅡClinical Trial of Oral Hexavalent Reassortant Rotavirus Attenuated Live Vaccine (Vero Cells)

Inclusion Criteria: 1. Healthy infants aged 6 to 12 weeks. 2. The legal guardian(s) is/are capable of understanding and voluntarily signing the informed consent form. 3. The legal guardian(s) is/are willing and able to comply with all follow-up visits, sample collection, vaccination, and other study procedures. 4. Able to provide valid legal identification documents. Exclusion Criteria: 1. Previous vaccination with any rotavirus vaccine. 2. History of rotavirus infection. 3. Gestational age \<37 weeks or ≥42 weeks at birth. 4. History of dystocia, neonatal asphyxia requiring resuscitation, or neurological impairment at birth. 5. Known hypersensitivity to any vaccine component (e.g., urticaria, dyspnea, angioedema). 6. Current diarrhea, vomiting, or other gastrointestinal disorders; gastroenteritis or any acute/chronic illness exacerbation within 7 days prior to vaccination; ongoing antibiotic/antiviral therapy. 7. History of intussusception or chronic gastrointestinal diseases, including congenital malformations predisposing to intussusception (e.g., Meckel's diverticulum). 8. Congenital malformations, developmental disorders, genetic defects, severe malnutrition, malignancies, or significant chronic conditions (e.g., Down syndrome, diabetes, sickle cell anemia, neurological disorders, Guillain-Barré syndrome). 9. Autoimmune or immunodeficiency diseases (including but not limited to asplenia, functional asplenia, HIV infection). 10. Household members with immunodeficiency/immunosuppression or undergoing/scheduled for immunosuppressive/cytotoxic therapy. 11. Coagulation disorders (e.g., clotting factor deficiencies, platelet abnormalities). 12. Immunosuppressive therapy for ≥14 days post-birth (prednisone ≥2mg/kg/day or equivalent), immunomodulatory/cytotoxic therapy, or planned use during the study. 13. History of severe neurological/psychiatric disorders (e.g., epilepsy, non-febrile seizures, convulsions) or relevant family history. 14. Postnatal administration of immunoglobulins/blood products (except hepatitis B immunoglobulin) or planned use during the study. 15. Previous participation in other investigational drug/vaccine studies or planned use during this study. 16. Receipt of live-attenuated vaccines within 14 days or subunit/inactivated vaccines within 7 days prior to enrollment. 17. Axillary temperature ≥38.0°C within the past 3 days. 18. Fever on scheduled vaccination day (axillary temperature \>37.0°C; measured ≥30 minutes post-feeding). 19. Currently or planning to participate in other vaccine or drug clinical trials. 20. Any other factors that the investigator deems unsuitable for participation in the clinical trial.