Benefits and risks of neonatal bacille Calmette-Guerin (BCG) vaccination among Aboriginal infants in Canada: Assessment by Markov model

Abstract

Bacille Calmette-Guerin (BCG) vaccine is given to Canadian Aboriginal neonates in communities at high risk for tuberculosis (TB). However, severe reactions and deaths associated with the vaccine have been reported among infants born with immunodeficiency syndromes. A Markov model was developed to estimate the burden of TB among Canadian Aboriginal children, evaluate the effectiveness of BCG vaccination, and estimate threshold values for severe combined immunodeficiency (SCID) incidence at which a BCG program will reduce quality-adjusted life expectancy. Estimated thresholds for SCID are lower than the rate reported in one North American Aboriginal population, regardless of the assumed risk of tuberculous infection. The possibility that Canadian Aboriginal children are at increased risk for SCID has serious implications for continued BCG use in this population. In this context, enhanced TB Control---including early detection and treatment of infection---may be a safer, more effective alternative.