BCG Aim- To induce a benign,aificial primary infection which will stimulate an acquired resistance to possible subsequent infection with virulent tubercle bacilli, and thus reduce the morbidity and moality from primary tuberculosis among those most at risk. WHO recommends the &;Danish 1331&; strain for vaccine production. Stable for several weeks at ambient temperature in a tropical climate and for upto 1 year if kept away from direct light and stored in a cool environment below 10 deg celcius. Vaccine must be protected from light ( wrapped up in a double layer of red/ black cloth). Normal saline is recommended as diluent for reconstituting the vaccine as distilled water may cause irritation. Reconstituted vaccine may be used within 3 hours. Dosage-0.1 mg in 0.1 ml volume. The dose of newborn below 4 weeks is 0.05 ml. Administered intradermally using tuberculin syringe. Injected slightly above the inseion of left deltoid. If injected too high / too low adjacent lymph nodes may become involved and tender. The vaccine must not be contaminated with an antiseptic/detergent. If alcohol is used to swab the skin , it must be allowed to evaporate before the vaccine is given. Phenomenon after vaccination:/ 2-3 weeks after a correct intradermal injection of a potent vaccine, a papule develops at the site of vaccination. It increases slowly in size and reaches a a diameter of about 4-8 mm in 5 weeks. It then subsides or breaks into a shallow ulcer but usually seen covered by a crust. Healing occurs within 6-12weeks leaving a permanent,tiny, round scar (4-8 mm in diameter).This is a normal reaction. Normally the individual become mantoux postive after 8 weeks has elapsed. Adverse reactions: prolonged severe ulceration at the site of vaccination, suppurative lymphadenitis, osteomyelitis and disseminated BCG infection. Contraindications: BCG should not be given to patients with generalised eczema, infective dermatosis, hypogammaglobulinemia , those with history of deficient immunity, patients under immunosuppressive treatment and in pregnancy. {Reference: park&;s textbook of preventive and social medicine, 23rd edition, pg no.196}