Phase IV Study of Concomitant Administration of the sIPV and HepA

Inclusion Criteria: * Age Requirement: Children aged 4 months at the time of enrollment * Vaccination Requirement: volunteers have already taken administration 2 doses of sabin-strain-based inactivated poliovirus vaccine (produced by IMBCAMS), and have not yet been injected with the third dose containing poliovirus antigen. * Provision of Legal Identification: Volunteers and their legal guardians or appointed representatives must provide valid legal identification documents. * Informed Consent: Legal guardians or appointed representatives of volunteers must have the capacity to understand the informed consent document and the research process, voluntarily participate, and sign the informed consent form. * Adherence: Legal guardians or appointed representatives of volunteers must be able to comply with the requirements in the study as well as complete relevant visits on time. * Birth condition: Full-term birth (37\~42 gestational weeks) and normal birth weight (no less than 2500g). * Temperature Requirement: Axillary body temperature prior to vaccination is less than 37.3°C. Exclusion Criteria: * Health Requirement: Volunteers cannot meet health requirements through physical examinations. * History of Related Illness: Volunteers have a history of developing Hepatitis A, poliomyelitis, or immunodeficiency. * Birth Condition: Volunteers have a history of abnormal labor stage, asphyxia, nervous system damage, or clinically confirmed pathologic jaundice。 * Allergic History: Volunteers have a history of allergies to any component of the investigational vaccine (e.g., aluminum hydroxide), any history of vaccine allergies, suspected allergies, or any other severe adverse reactions. * Vaccine History: Volunteers received any inactivated vaccines or subunit vaccines within 7 days (including the 7th day) prior to vaccination with the investigational vaccine, or any other live attenuated vaccines within 14 days (including the 14th day) prior to vaccination. * Acute Illness: Volunteers have experienced acute illnesses (e.g., fever) within 3 days prior to vaccination with the investigational vaccine. * Neurological and Mental Health: Volunteers have a history of seizures, convulsions, cerebral palsy, epilepsy, mental illness, or a family history of such conditions. * Health Conditions: Volunteers have known congenital abnormalities, developmental disorders, genetic defects, or severe malnutrition, among other conditions. * Coagulation Abnormalities: Volunteers have a history of coagulation disorders (e.g., coagulation factor deficiency, coagulation disorders). * Infectious Diseases: Volunteers have infectious diseases that may affect the study, such as human immunodeficiency virus (HIV) infection, hepatitis, and tuberculosis. * Special Condition: Volunteers who could not tolerate venipuncture, or had a history of needle and blood sickness. * Organ Removal History: Volunteers have a history of organ removal (e.g., thyroid, pancreas, liver, spleen). * History of Blood Products: Volunteers have a history of loss of blood, blood transfusion, the use of adjuvant therapies, or immunoglobulin within 3 months prior to vaccination. * Immune Therapy: Volunteers have received immune-enhancing or immune-suppressing therapy within the last 3 months (continuous oral or intravenous administration for more than 14 days) prior to vaccination. * Participation in Other Clinical Studies: Volunteers are currently or have plans to participate in other clinical studies before enrollment. * Investigator's Discretion: The final exclusion criterion is the investigator's discretion to determine whether a volunteer is suitable for participation in the study.