UNIVERSAL BACILLE CALMETTE-GUERIN (BCG) VACCINATION IN ECUADOR: A COST EFFECTIVENESS ANALYSIS

Purpose: Pediatric tuberculosis (TB) in Ecuador has decreased, leading to exploration of alternative BCG vaccination strategies rather than the current universal pediatric use. Since 80% of TB cases occur in Coastal Ecuador, focusing BCG use there could be considered.

Method: We developed a Markov model to estimate the cost-effectiveness of regional BCG vaccination strategies compared to universal use in children aged <15 years. The model simulates active TB rates in Ecuadorian children under 4 possible vaccination scenarios: universal (current), Coast region only, Coast and Amazon (3% of TB cases, second highest incidence per 100 000 people) regions and no BCG. Parameters included an overall annual pediatric TB risk of 0.0067%, BCG effectiveness (range) 73% (50-80%), cure rates for initial TB treatment 78% (62-80%), and TB retreatment 35% (30-50%). Costs were derived from Panamerican Health Organization and Ecuador Ministry of Public Health sources in US$, the Ecuadorian currency. Our effectiveness measure was quality-adjusted life years (QALYs). A health system perspective was taken and outcomes were discounted 3% per year over a 15 year time horizon

Result: Vaccinating only the Coast region cost $125 per quality-adjusted life-year (QALY) gained compared to no vaccination; universal BCG cost $303/QALY compared to the Coast strategy. The Coast and Amazon regions strategy was dominated. Model results were robust to individual variation of all parameter values. Universal BCG use would be economically reasonable unless the overall TB risk is less than 0.00034% per year. In a probabilistic sensitivity analysis, universal vaccination was favored in 93% of model iterations at a willingness to pay threshold of $5,456/QALY (Ecuador’s per capita GDP)

Conclusion: Despite decreasing pediatric TB, universal BCG vaccination remains a highly cost-effective strategy in Ecuadorian children unless overall TB risk decreases >95%, to <0.00034% per year.