PCV24 Clinical Trial in Infants and Young Children Aged 2 Months (Minimum 6 Weeks) to 71 Months

Inclusion Criteria: * Healthy subjects aged 2 months (minimum 6 weeks) and 7-71 months, whose guardians can provide valid identification documents for both the subjects and themselves, as well as proof of their guardianship relationship. * The guardians of the subjects voluntarily agree to their participation in this trial, sign the Informed Consent Form (ICF), and are willing to comply with all requirements of this clinical trial protocol. * The guardians of the subjects have the ability to understand the trial procedures (non-illiterate). Exclusion Criteria: * Subjects who have received any type of pneumococcal vaccine prior to enrollment, plan to receive a pneumococcal vaccine during the trial, or have a history of invasive diseases caused by Streptococcus pneumoniae (confirmed by any clinical, serological, or microbiological method). * Subjects with abnormal physical examination results that are deemed clinically significant by a clinician. * Subjects with suspected or confirmed fever (axillary temperature ≥ 37.5℃) within 3 days prior to enrollment; or those with an axillary temperature ≥ 37.5℃ on the day before the first dose of vaccination. * Subjects with a history of acute illness, acute exacerbation of chronic illness, systemic use of antibiotics or antiviral drugs within 3 days prior to the first dose of vaccination; or those who have taken antipyretic, analgesic, or antiallergic drugs (e.g., acetaminophen, ibuprofen, loratadine, cetirizine, etc.) within 3 days p…