The study aimed to evaluate the safety and immunogenicity of a Sabin strain-based inactivated polio vaccine in infants aged two months (60~89 days).

Inclusion Criteria:

1. Healthy permanent residents aged 2 months (60~89 days);
2. Infant's legal guardians agree to sign the informed consent forms voluntarily;
3. Infant's legal guardians are able to comply with the requirements of the clinical trial protocol;
4. Armpit temperature ≤ 37.0 ℃

Exclusion Criteria:

1. preterm birth (gestational age < 37 weeks);
2. the presence of congenital malformations, developmental disorders, genetic defects, or severe malnutrition;
3. had a history of poliomyelitis;
4. had a personal or family history of allergy, convulsions, epilepsy, encephalopathy, or psychiatric disorders;
5. had known hypersensitivity to any component of the study vaccine or a history of severe allergic reaction (e.g., anaphylaxis) to any previous vaccination;
6. had immunodeficiency or receipt of immunosuppressive therapy;
7. diagnosed coagulation disorders (including factor deficiencies, coagulopathies, platelet abnormalities) or evidence of significant bruising/bleeding diathesis;
8. had known or investigator-suspected concurrent acute or active chronic diseases (including respiratory, cardiovascular, hepatic, renal, or dermatological conditions) or acute infection, or maternal HIV infection;
9. occurrence of fever (axillary temperature ≥ 38.0 °C) within the 3 days preceding enrollment;
10. had acute illness requiring systemic antibiotic or antiviral treatment within the 7 days preceding enrollment;
11. administration of blood products within the 3 months preceding enrollment;
12. had receipt of any live attenuated vaccine within the 14 days preceding enrollment;
13. had receipt of any inactivated or subunit vaccine within the 7 days preceding enrollment;
14. had recent administration of any other experimental product and any other condition deemed by the investigator as potentially interfering with the assessment of trial outcomes.