5.bcg & chemo
TRANSCRIPT
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