Phase Ib/IIa Clinical Trial of SIBP-A16 Injection in Premature Infants and Full-term Infants

Inclusion Criteria: * During screening, infants within 1 year of age, including premature infants (gestational age ≥29 to \<35 weeks) and full-term infants (gestational age ≥35 weeks), with underlying diseases but no other risk factors, are allowed to participate in the trial; * Infants with a body weight ≥3 kg at screening; * Infants who are entering their first RSV infection season at screening; * Parents/legal guardians of trial participants have signed the informed consent form; * Parents/legal guardians of trial participants are able to understand and comply with the requirements and procedures of the protocol, including scheduled center visits, telephone interviews, and blood sample collection; * Participants can complete the follow-up period, which is approximately 1 year after the administration of the study drug. Exclusion Criteria: * Any fever (≥37.5°C, axillary temperature) or acute illness (defined as the presence of moderate or severe symptoms or signs) occurring within 7 days prior to drug administration; * Having experienced Lower Respiratory Tract Infections (LRTI) within the previous 7 days prior to randomization, or having active LRTI at the time of randomization; * Individuals with chronic eczema or urticaria, or those with an allergic constitution who are allergic to multiple drugs, or those with a known history of allergy to immunoglobulin products, blood products, other exogenous proteins, or any components of this product; * Had a history of RSV infe…