This vaccine contains live bacteria, harmless strain related to the TB bacteria. It gives about 70% protection.

BCG injection is a safe vaccine if given with care by qualified persons. Adverse effects including abscesses and large scars are mainly due to faulty techniques.

However, perhaps the best prevention against TB is to have a strong body defense system. Keep a healthy lifestyle and exercise regularly. Do not be overly stressed. TB strikes hard when your body immunity is low and your health is poor.