Inclusion Criteria: Participants who meet all the following criteria may be included in the study:
1. Age 42 to 56 days, inclusive, at the time of Dose 1
2. Good general health status, as determined by medical history, physical examination, vital signs, and clinical judgment
3. Product of normal full-term pregnancy (37 to 42 weeks' gestation)
4. Birth weight ≥ 2000 g
5. Length and weight ≥ -2 standard deviations (SD) for age and sex, according to the Philippine national child growth standards (see Appendix 1)
6. Willingness of parent/guardian for the child to attend all protocol visits and to have all protocol-required procedures
7. Provision of written informed consent by legally acceptable representative
Exclusion Criteria: Participants who meet any of the following criteria will be excluded from the study:
1. Congenital abnormality or serious chronic disorder requiring treatment or likely to affect normal growth or development
2. Any condition that may increase risk of study participation or interfere with interpretation of study results
3. Immunodeficiency or chronic administration (\> 14 consecutive days) of immunosuppressant or other immune-modifying drugs (see details in Section 6.6.2), including systemic glucocorticoids, within 6 months before Day 1 (topical, intra- articular, or inhaled glucocorticoids permitted)
4. History of sepsis or pneumonia
5. History of anaphylaxis or angioedema
6. History of severe reaction to immunization
7. Known hypersensitivity to any of the ingredients in either IVT PCV-25 or Prevnar 20
8. Contraindication to any concomitant vaccine or to Prevnar 20, according to each vaccine's product information
9. Prior receipt of a licensed or investigational pneumococcal vaccine
10. Prior receipt of any diphtheria, tetanus, pertussis, Hib, or polio vaccine
11. Prior receipt of \> 1 dose of HepB vaccine
12. Receipt of HepB vaccine at age ≥ 30 days
13. Receipt of an inactivated vaccine within 14 days before Day 1 or planned receipt through Day 85 other than as described in Section 6.6.1 and Section 6.6.3
14. Receipt of a live vaccine within 28 days before Day 1 or planned receipt through Day 85 other than as described in Section 6.6.1 and Section 6.6.3
15. Receipt of blood transfusion or blood products before Day 1 or planned receipt through Day 85
16. Receipt of any other IP before Day 1
17. Planned elective hospitalization or surgical procedure through the end of the study
18. Family member of employee of Inventprise, vendors, or research sites associated with the study
19. Any medical, psychiatric, or social condition, or occupational or other responsibility of the parent/guardian that, in the judgment of the Investigator, would interfere with or serve as a contraindication to protocol adherence, assessment of safety (including reactogenicity), or an ability to provide informed consent
Temporary Delay Criteria: administration of IVT PCV-25 / Prevnar20 will be delayed for any participant who meets any of the following criteria:
1. Receipt of any inactivated vaccine within 14 days or any live vaccine within 28 days
2. Febrile illness (eg, temperature ≥ 38.0°C) or other acute illness within 48 hours
3. Any other signs or symptoms or medication use that could inhibit the proper vaccine administration of the IP or interpretation of diary data
