Assessment of effectiveness:~In cohort 1, the injection site reaction was examined at 0min, 24h, 48h and 72h after skin test, and the transverse and longitudinal diameters of the erythema and induration were measured and recorded in millimeters (mm), the larger the erythema or induration. Any blisters, necrosis, lymphangitis should be faithfully recorded.~In cohort 2, the injection site reaction was examined at 0min and 48-72 h after skin test, and the transverse and longitudinal diameters of the erythema and induration were measured and recorded in millimeters (mm), the larger the erythema or induration. Any blisters, necrosis, lymphangitis should be faithfully recorded.~Safety assessments:~The safety assessment included all expected and unexpected medical events that occurred during the observation period of the clinical trial (within 72 hours after the skin test) and were related or unrelated to the injection of the investigational drug. These included specific reactions such as redness, induration, blister, necrosis, and lymphangitis at the injection site (palmar forearm). Common and occasional adverse reactions include:~Local adverse reactions: injection site pruritus, injection site pain, injection site rash;~Systemic adverse reactions included fever, headache, nausea, fatigue, myalgia, diarrhea, vomiting, paresthesia.
Cohort 1 was a randomized, double-blind, controlled clinical trial with a planned enrollment of 500 patients. Cohort 2 is a non-randomized, open-label clinical trial with a planned enrollment of approximately 60000 patients. Cohort I was injected with EC and TB-PPD in both arms, and cohort II was injected with EC only