13-valent pneumococcal conjugate vaccine(Fosun Adgenvax Biotechonology)

This study is a phase III clinical trial to evaluate the immunogenicity and safety of the 13-valent pneumococcal conjugate vaccine (multivalent conjugate) in infants aged 2 months (at least 6 weeks) and 3 months. The main objectives of the study include: 1. To evaluate the immunogenicity of the trial vaccine in infants aged 2 months (at least 6 weeks) following the corresponding immunization schedule compared to the control vaccine; 2. To evaluate the immunogenicity of the trial vaccine in infants aged 3 months following the corresponding immunization schedule compared to the 2-month group; 3. To evaluate the safety of the trial vaccine in infants aged 2 months (at least 6 weeks) and 3 months following the corresponding immunization schedule.