LIMITATIONS OF BCG :-

• Waning of protective immunity with time. Published data suggests that duration of protection is not more than 10 years.
  
  
• Data from different studies indicates that BCG efficacy ranges from 0-80%.
  
  
• Effectiveness is reduced in disseminated tuberculous disease.
  
  
• Problem of a live vaccine in immunocompromised host.
  
  
• Not protective against reactivation of tuberculosis or HIV associated Koch's.
  
  

• Rationally attenuated Mycobacterium Tuberculosis.
  
  
• Recombinant BCG.
  
  
  • Current TB vaccine strain mycobacterium bovis BCG endowed with a pose forming cytolysin.
    
    
  • V. Salmonella typhimurium secreting a single immunodominant antigen shared by BCG and mycobacterium tuberculosis.
    
    

• Over expressing Mycobacterium Tuberculous Antigen.
  
  
• Protein subunit vaccine
  
  
• DNA Vaccines
  
  

• BCG & LBW Infant : BCG vaccine and OPV administered in early neonatal life showed successful BCG reaction in 95.5% Infants.
  
  
• One recent study from India suggested that BCG vaccination has an immunomodulatory role in case of IDDM & NIDDM.
  
  
• BCG & Other Vaccines : Administration of BCG at the time of priming markedly increased the cellular & antibody responses to Hepatitis B & oral polio vaccine.
  
  

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