5.bcg & chemo

BCG VACCINATIONCalmette & Guerin, two French scientists who discovered BCG in 1906

Attenuated avirulent strain of M. bovis231 subcultures for 13 yearsorally(1921to1925)Intradermally(1927 onwards)trials:

regarding the efficacy and protective value of BCG one particular trial was conducted in south India

( Chengalpet & Bangalore, 1968)

AIMBCG vaccine

Induce primary artificial infection

Increases systemic immune response

Resistance to virulent TB bacilli

Decrease mortality and morbidity

VACCINELive bacterial vaccineAttenuated strain of M.bovisDANISH 1331 recommended strain for

vaccine production in BCG lab at Guindy, Chennai

The vaccine is stored in refrigerator at temperature <10oC

TYPESTwo types Freeze dried liquid vaccine Freeze dried vaccine

Stable vaccinePresent day vaccine in

hospitalsVaccine must be protected

from sunlight exposure by wrapping in black cloth.

Reconstituted vaccine By diluting the

vaccine with normal saline

DOSAGEfor adult : 0.1mg in 0.1ml(intradermally) For newborn(<4wks) : 0.05ml (skin thin and full

doseabscess formation) Administration

By tuberculin syringeOther techniques not so much effectiveInjected intradermally at deltoid insertion (inj too high or low tender node formation)

AGEIndia : at birth or at 6 weeks(along with DPT and Polio)

Early administration Increase protection against childhood TB and TB meningitis

Phenomena after vaccination

Vaccine

Papule(2-3 wks after)

increase in size 4to8mm(in 5 wks)

shallow ulcer with crust formation

healing occur at 6to12 wks

scar 4-8mm in dia

COMPLICATIONSprolonged ulceration(1-10%)suppurative lymphadenitis(1-10%)

osteomyelitisdisseminated BCG inf(<1%)death

Ulcerated, 3 x 2 cm in diameter, erythematous, cutaneous nodule

COMPLICATIONS cont…after vaccination

local abcess formation

may recover spontaneously

may recover after aspiration

if not recover after aspiration

excise the abscess and excise the abscess and locally apply PAS or INH locally apply PAS or INH

powder dailypowder daily

PREVENTION OF COMPLICATIONto prevent the complication

vaccine to be given intradermally

no vaccine into the same arm for 6 months

EFFICACY OF BCG VACCINEpreventing TB = 51%preventing death = 71% case control studies

protective efficacy = 50%duration of protection = 15to20yrsrange of protection = 0-80%

prospective prospective

trialstrials

efficacy variation due to difference in

exposure of population to non Tuberculous bacilli

strains of BCG vaccineage of administrationtime of vaccination and development of TBnutritional status of vaccine receipient

REVACCINATIONrevaccination has not been included in

routine EPI of India may be given at school age

CONTRAINDICATIONS inf. Dermatosis eczema hypogammaglobulinemia immunocompromised immunosuppressive ppl pregnancy

direct BCG vaccination(without prior tuberculin test)has been adopted in India due to

more rapid vaccination complete coverage reducing cost expense no adverse reaction even if tuberculin

positive administered as quick as possible in

infancy before exposing

IMPACT BCG vaccination value < case finding and

chemotherapy Little value in TB prevention

BCG VACCINATION AND HIV INFECTION Previously BCG vaccine can be given to

all infants unless the child presented with symptomatic HIV

Presently, acc to GACVS recommend BCG should not be given to those infants who are asymptomatic HIV infection

COMBINED VACCINATIONCombined with OPV and DPT (in diff arm)

In industrialized countries, policy on BCG vaccination change in the upcoming years; BCG given only to high risk people.

TO SUM UPBCG has more value in preventing childhood TB and TB meningitis and miliary TB

CHEMOPROPHYLAXISFor childhood tb

INH 5mg/kg OD for 1 year (protection for 30 years)

For adult INH 300mg OD for 1 year

(now 9months)

outcome INH prophylaxis reduces the risk upto

90%

Chemoprophylaxis not effective in India Costly exercise Not effective INH induced hepatitis

Conclusion BCG value > chemoprophyaxis