Q. What is a BCG vaccine?
A. BCG vaccine is a live bacterial vaccine given for protection against tuberculosis, mainly severe forms of childhood tuberculosis. It stands for Bacillus Calmette Gurrain, the strain of bovine tuberculosis used in the vaccine & attenuated by French scientists Calmette & Gurrain.

Q. How is BCG vaccine available?
A. BCG vaccine is available as a lyophilized powder in an ampoule. Diluent used is buffered saline that is available separately. It is available in a multidose ampoule containing 20 doses.

Q. How is BCG vaccine stored?
A. BCG vaccine stocks can be stored frozen in freezer compartment. Working stock can be stored in the chiller compartment. Even diluents should be stored in the refrigerator's lower racks at 2-8^oC.

Q. How is BCG prepared?
A. BCG vaccine ampoules should be cut with a file very slowly & not snapped open because it has vacuum inside or else the glass will splinter and fly if cut very suddenly. It may be safer to hold the ampoule in a cloth to avoid injury should the glass splinter. Once prepared, BCG vaccine should be used within 2-3 hours & discarded thereafter.

Q. When is BCG given?
A. BCG is given anytime from birth to 15 days of life along with the zero dose of oral polio vaccine. It is to be given to all children as part of EPI schedule as recommended by Govt. of India.

Q. How is BCG vaccine given?
A. BCG vaccine is given intradermally i.e. in the layers of skin using 26 no. needle. It is given conventionally over left deltoid area (to differentiate it from small pox vaccine scar, which was conventionally given over right deltoid area). 0.1 ml of vaccine is given using BCG syringe which is a 1 ml. glass syringe with steel plunger to identify it so that it is not used for any other purpose. A wheal or swelling of 6 mm is raised above the surface. No spirit or antiseptic should be applied over the site before injection. Good bath with soap and water is enough to clean the local injection site. At the most one can use normal saline to clean the area.

Q. When is a booster dose of BCG vaccine given?
A. Neither Govt. of India nor Indian Academy of Pediatrics recommends a booster dose of BCG in India. Some countries like in Gulf recommend one or more booster doses.

Q. What is the efficacy of BCG vaccine?
A. In a country like ours where tuberculosis is endemic, children catch the germs early in life & develop primary complex. In children younger than 3-5 years of age, this can spread & lead to severe & serious forms of childhood tuberculosis like tuberculous meningitis, disseminated tuberculosis, miliary tuberculosis, tuberculosis of organs like bones, urinary tract etc. BCG being live vaccine itself induces a benign primary complex, which leads to some immunity. Such a child when comes in contact with a patient with tuberculosis can still catch the wild germ and develop primary complex, but the spread will be mostly prevented by previous BCG immunity. Hence such children will not develop serious forms of childhood tuberculosis. Such children when they grow as adults can catch tuberculosis again & develop adult form of tuberculosis which is a different type of tuberculosis altogether. This adult type of tuberculosis is not prevented by BCG. Hence BCG does not prevent primary complex but prevents spread of the primary complex & hence the severe forms of childhood tuberculosis. This explains the outcome of the famous Chingleput trial on BCG vaccine efficacy, which failed to show the protective efficacy of BCG against adult type of tuberculosis.

Incidentally BCG also cross protects against leprosy & the efficacy is 20%.

Q. What is the normal reaction to BCG vaccine?
A. Immediately after the BCG vaccine there is a small swelling at the injection site which persists for 6-8 hours. After that the swelling disappears & the injection site looks normal. After 6-8 weeks a swelling reappears which looks like a mosquito bite. It grows in size & forms a nodule which breaks open & discharges some fluid & forms an ulcer. The ulcer heals by forming a scar. The whole process takes 2-5 weeks. Some times this process of ulceration & healing recurs 2-3 times. Ultimately the typical puckered scar is formed which remains for lifetime.

If ulceration occurs within 7 days of injection, one must report to the doctor, as it may be a sign of tuberculosis in the child.

Q. What local care should we take at injection site?
A. Injection site should not be pressed or rubbed. It should not be fomented. Nothing needs to be applied locally. Infact, bath with soap and water should suffice even when it has ulcerated.