ABSTRACT
Hepatitis B is a common problem in many countries. Due to high efficacy, safety and low cost of vaccine, mass immunization has become a favorite strategy to improve population health. In this study, we tried to estimate marginal effectiveness of adolescents' immunization program in Iran. Epidemiologic data about of hepatitis B in Iran was gathered through literature review, expert opinion, existing resources of data and synthesis by modeling of other data. In a state transition model, different stages of disease were simulated in 15 to 100 year old individuals. Comparing the results of burden of hepatitis B with and without immunization revealed an estimate of avoidable burden of disease with intervention. Monte Carlo simulation and sensitivity analyses were done for uncertainty analysis of results. Immunization of around one million 15-year, old males and females prevents 2071 of male and 581 of female premature deaths due to acute hepatitis B, cirrhosis and hepatocellular carcinoma annually. Moreover, it prevents loss of about 52 and 36 percent of YLL [years of life lost] due to hepatitis B complications in males and females respectively. On average, it avoids loss of Disability Adjusted Life Years [DALY] of 0.012 and 0.006 years, according to present value of life. Monte Carlo simulation of populations showed that effectiveness of the intervention is quite significant and about half of males and one third of females with disability, equal to at least one year of full health, will be free. With sensitivity analyses, results were standing in acceptable limit of values in both bivariate and probabilistic calculations. Our study showed that effectiveness of adolescents' immunization against hepatitis B is quite significant. Calculation using basic estimates of cost of intervention program implies that this intervention is possibly very cost effective. For final judgment, results should be combined with cost effectiveness analysis, and compared to other interventions