Recommendations for UseThe recommended age of administration is at birth (for institutional deliveries) or at 6 weeks with other vaccines. Catch up vaccination with BCG is recommended till the age of 5 years. Routine tuberculin testing prior to catch up vaccination is not necessary. BCG may be repeated once in children less than 5 years of age in the absence of a reaction/scar presuming that BCG has not been taken up (even though most patients with absent reactions/scars have shown in vitro evidence of cell mediated immunity against tuberculosis). Here again tuberculin testing prior to administration of the second dose of BCG is not necessary. If no reaction is seen at the local site even after 12 weeks, it is an indication to repeat BCG, on the presumption that BCG has not taken up. |
Adverse reactionsThe ulcer at the vaccination site may persist for a few weeks before formation of the final scar. No treatment is required for this condition. Secondary infection at the vaccination site may require antimicrobials. Ipsilateral axillary/cervical lymphadenopathy may develop a few weeks/months after BCG vaccination. Antitubercular therapy is of no benefit in such situations and should not be administered. The nodes regress spontaneously after a few months. It should also be noted that if fine needle aspiration cytology of the nodes is carried out, stain for acid-fast bacilli may be positive. These are bovine vaccine bacilli and should not be misconstrued as being suggestive of tuberculous disease. In some children the nodes may even liquefy and result in an abscess. Surgical removal of the nodes or repeated needle aspiration is the treatment of choice. Antitubercular therapy is not recommended in this situation also. Disseminated BCG infection is extremely unusual but may occur in children with cellular immunodeficiency. |
The exact burden of childhood tuberculosis in India is unknown but it is believed to constitute 15-20% of all tuberculosis cases. It is also estimated that childhood tuberculosis is responsible for . 10% of all childhood hospital admissions and . 10% of childhood deaths in developing countries such as India. Prevention of childhood tuberculosis is thus an important priority but is unfortunately difficult because of the limited efficacy of the BCG vaccine.
BCG vaccine is derived from the bovine tuberculosis strain and was first developed in 1921. It was the result of painstaking efforts by the French microbiologist Albert Calmette and the veterinary surgeon Camille Guerin who performed 231 repeated subcultures over 13 years. It continues to be the only effective vaccine against tuberculosis. The two common strains in use are Copenhagen (Danish 1331) and Pasteur of which the former was produced in India at the BCG laboratories, Guindy, Tamil Nadu till recently. BCG induces cell-mediated immunity but the protective efficacy is a matter of debate and is very difficult to quantify. BCG has an efficacy of 50-80% for prevention of miliary and meningeal form of the disease. Protective efficacy for pulmonary tuberculosis is around 50%.
The vaccine contains 0.1.0.4 million live viable bacilli per dose. It is supplied as a lyophilized (freeze-dried) preparation in vacuum sealed multi-dose dark colored ampoules or 2 ml vials with normal saline as diluent. The vaccine is light sensitive and deteriorates on exposure to ultraviolet rays. In lyophilized form it can be stored at 2 to 8° C for up to 12 months, without losing its potency. The long necked BCG ampoule should be cut carefully by gradual filing at the junction of its neck and body, as sudden gush of air in the vacuum sealed ampoule may lead to spillage of the contents. Diluent should be used for reconstitution. Sterile normal saline may be used if diluent is not available. As the vaccine contains no preservative, bacterial contamination and consequent toxic shock syndrome may occur if kept for long after reconstitution. The reconstituted vaccine should be stored at 2 to 8°C, protected from light and discarded within 4-6 hours of reconstitution.
The recommended dose is 0.1 ml or 0.05 ml as suggested by the manufacturer of the vaccine. Dose not depend on the age and weight of the baby. Injection of BCG should be strictly intradermal, using a tuberculin syringe and a 26G/27G needle. The convex aspect of the left shoulder at level of deltoid insertion is preferred for easy visualization of the BCG scar and for optimum lymphatic drainage. Other sites such as thigh should be avoided. The selected site may be swabbed clean using sterile saline and local antiseptics should be avoided. A wheal of 5 mm. at the injection site indicates successful intradermal administration of the vaccine. Subcutaneous administration of BCG is associated with an increased incidence of BCG adenitis.
The injected site usually shows no visible change for several days. Subsequently, a papule develops after 2-3 weeks, which increases to a size of 4-8 mm. by the end of 5-6 weeks. This papule often heals with ulceration and results in a scar after 6-12 weeks. The ulcer at vaccination site may persist for a few weeks before formation of the final scar. No treatment is required for this condition. Secondary infection at the vaccination site may require antimicrobials. Ipsilateral axillary/cervical lymphadenopathy may develop a few weeks/ months after BCG vaccination. Antitubercular therapy is of no benefit in such situations and should not be administered. The nodes regress spontaneously after a few months. It should also be noted that if fine needle aspiration cytology of the nodes is carried out, stain for acid-fast bacilli may be positive. These are bovine vaccine bacilli and should not be misconstrued as being suggestive of tuberculous disease. In some children the nodes may even liquefy and result in an abscess. Surgical removal of the nodes or repeated needle aspiration is the treatment of choice, again antitubercular therapy is not recommended. Disseminated BCG infection is extremely unusual but may occur in children with cellular immunodeficiency.
BCG should be avoided in the
immunocompromised especially those with cellular immunodeficiency;
it may however be given at birth to children born
to HIV positive mothers. BCG may be given with all vaccines
on the same day or at any interval with the exception of
measles/measles mumps rubella (MMR) vaccine where a gap
of 4 weeks between the two vaccines is recommended.