What is BCG vaccine?
BCG is bacillus calmette guerin.
It ia vaccine to prevent tuberculosis and sever tuberculosis.
BCG vaccine is derived from the bovine tuberculosis strain.
It was first developed in 1921 by the French microbiologist, Albert Calmette, and the veterinary surgeon, Camille Guerin.
It continues to be the only effective vaccine against tuberculosis.
The two common strains in use are Copenhagen (Danish 1331) and Pasteur.
Copenhagen (Danish) was produced in India at the BCG Laboratories, Guindy, Tamil Nadu till recently.
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.
What type of vaccine is BCG?
BCG vaccine is a live vaccine.
They are live bacteria without capacity to cause disease.
After injecting it the recipient's immunity fights against it like it fights real infection.
Thus the recipient is prepared for actual real infection caused by disease causing bacteria by developing their immunity.
This is form of active immunity that is recipient generates immunity actively in itself.
Why is BCG vaccine necessary?
More than 1 million cases of pediatric tuberculosis occur every year.
The proportion of pediatric TB cases registered are increasing.
Prevention of childhood tuberculosis is thus an important priority.
How it is stored?
The vaccine is light sensitive and exposure to ultra violet rays.
In lyophilized form, it can be stored at 2 to 8 degree C for up to 12 months without losing its potency.
How is it administered?
Diluent is for reconstitution.
Sterile normal saline can be used in place of diluent.
BCG vaccine contains no preservative.
The reconstituted vaccine is stored at 2 to 8 C, protected from light and is discarded within 4–6 hours of reconstitution.
The recommended dose is 0.1 ml or 0.05 ml.
Dosage does not depend on the age and weight of the baby.
BCG injection is strictly intradermal, using a tuberculin syringe and a 26G / 27G needle.
Left shoulder at level of deltoid insertion is preferred for injection.
The selected site is swabbed clean using sterile saline and local antiseptics are avoided
What happens after BCG injection?
A wheal of 5 mm at the injection site indicates successful intradermal administration of the vaccine.
BCG adenitis is seem more commonly after subcutaneous administration.
Usually shows no visible change for several days.
Subsequently, a papule after 2–3 weeks.
Which increases to a size of 4–8 mm at end of 5–6 weeks.
Papule heals with ulceration.
Scar after 6–12 weeks.
In some cases ulcer at injection site persists for weeks before scar appears.
No treatment is required for this condition.
Secondary infection at injection site may require antimicrobials.
Ipsilateral axillary/cervical lymphadenopathy can occur a few weeks/months after BCG injection.
Antitubercular therapy is of no benefit in such situations and should not be given.
The nodes regress spontaneously after a few months.
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.
Disseminated BCG infection can occur but is extremely rare, may occur in babies with cellular immunodeficiency.
BCG should be avoided in the immunocompromised, especially those with cellular immunodeficiency.
When is BCG vaccine given?
At birth (for institutional deliveries) or at 6 weeks.
Catch up vaccination with BCG is recommended till the age of 5 years.
Routine tuberculin testing before catch up vaccination is not needed.
BCG is repeated once in children less than 5 years of age in the absence of a reaction/ scar.
How efficacious is BCG vaccine?
It decreases 75–86 % chances of getting miliary and meningeal form of the tuberculosis.
It decreases chances of getting pulmonary tuberculosis by 50%.
- Should be given at birth or at first contact
Catch up vaccination:
- May be given up to 5 years
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