The purpose of this study is to investigate the efficacy and safety of GC3107 in healthy infants

The study will be conducted in 2 Countries, Korea and Thailand. About 750 subjects will be enrolled to this study.

This clinical trial consists of Part 1 to compare the efficacy and safety between the study group and the active control group and Part 2 for the final safety assessment. Subject enrollment for Part 1 and Part 2 will occur at the same time, and subjects who meet the final inclusion/exclusion criteria will be randomized to Part 1 or Part 2 via the IWRS.

When the legally acceptable representative of the subject within 4 weeks after birth consents to participate in the clinical study in writing at Visit 1, the protocol-mandated examination and tests will be performed at each visit, and only the subjects who meet the inclusion/exclusion criteria will be assigned randomization numbers and receive a single intradermal injection of the investigational product. However, the informed consent of the subject's legally acceptable representative for participation in the clinical trial may be obtained between 36 weeks of pregnancy of a subject's mother and Visit 1.

The investigator will instruct the subject's legally acceptable representative to record any adverse events (AEs) occurring after administration of the investigational product to assess the safety of the subject during the study period.

The subjects participating in Part 1 will have the tuberculin skin test at Visit 4 for the efficacy assessment and receive an intradermal injection of 0.1 mL purified protein derivatives (PPD) reagent. Visit 5 will occur within 48 to 72 hours of the PPD reagent injection to check the tuberculin skin test results.

Also, Visit 6 will be conducted as an on-site visit to check for any solicited local AEs (abscess, ulcer, scar, and BCG lymphadenitis) and unsolicited AEs occurring until 6 months (168 days) after administration of the investigational product.

Inclusion Criteria:

1. Subject's legally acceptable representatives had this clinical trial information explained to them and understood it, voluntarily decided participation, and provided informed consent
2. Healthy infants aged≤4weeks
3. Body weight≥2,500g at birth
4. Born after normal gestation(≥37weeks)

Exclusion Criteria:

1. Had contact with patients with a confirmed diagnosis of active pulmonary tuberculosis
2. Any symptoms or signs of active tuberculosis infection or current treatment of tuberculosis at screening
3. History of confirmed tuberculosis
4. Acute fever with tympanic temperature≥38.0 'C within 24 hours prior to administration of the investigational product, or an active infections disease at screening
5. Hypothermia with tympanic temperature<36.0 'C within 24 hours prior to administration of the investigational product
6. Clinically suspected neonatal sepsis
7. Born with severe congenital anomaly that may affect the efficacy or safety result of this clinical trial as judged by the investigator
8. Severe skin disease or burn at the injection site of investigational product
9. The subject's mother had human immunodeficiency virus (HIV)-positive result on prenatal testing