Bacillus Calmette-Guérin (BCG) 

BCG (Bacillus Calmette- Guerin) is a live attenuated strain of Mycobacterium bovis which is a vaccine to prevent childhood tuberculos meningitis and miliary disease in Tuberculosis prevalent countries. It is ineffective against tuberculosis affecting respiratory system which is more common in adults. Protection lasts about 10-15 years. 

BCG is part of neonate immunization program in many countries which has high prevalence of tuberculosis. It is also recommended to healthcare workers, laboratory workers and veterinary staff who are at higher risk exposure to tuberculosis. 

Contraindications to BCG vaccine

1. Those who have anaphylactic reaction to content of vaccine. 
2. Pregnant women should not receive BCG vaccination. 
3. Immuno-compromised patients i.e. those who have HIV , on long term steroids, cancer patients and those who have organ transplants should not take this live vaccine. 

Dosage

BCG vaccine is injected intradermally, ideally with another live vaccine like MMR. If it cannot be given together it should be spaced 4 weeks apart from another live vaccine. No other injection should be given into that arm till 3 months later because there is risk of lymphadenitis. 

For infants below 12 months old : 0.05 ml  of BCG vaccine
For children above 12 months old and adults: 0.1 ml of BCG vaccine 

Possible post vaccine reaction

The usual reaction post vaccination is an indurated papule at injection site for 2-3 weeks after which some may ulcerate and slowly subside over months leaving a small flat scar. Some may have an enlarged lymph node. 

Minor side effects from vaccine include headache, enlarged lymph node and fever. Severe vaccination reactions may occur in some people. It may result in big ulcers, abscess formation and large keloid formation.  The abscess and indurated lymph node can be incised and drained. 

Serious complications include anaphylactic reaction to the vaccine and disseminated BCG infection like oteomyelitis and osteitis. But this is very rare.  These patients should be managed by the respiratory physician and pediatrician.