Introduction & Objective: Brucellosis is an important zoonosis considered a serious hazard to public health . Human brucellosis is caused by one of the four species of the brucella genus: B. melitensis is principally found in goats and sheep, B. abortus in cattle, B. suis in swine and B. canis in dogs. Vaccination of young animals, is a strategy to decrease the incidence rate of brucellosis in humans. The objective of this study is to give an estimate of vaccination coverage in animals (sheep or goats and cattles) and its effect on human brucellosis incidence rate. Materials & Methods: In this cross-sectional study, the data on reported human cases of brucellosis originated from Hamadan health deputy and the data on animal vaccination was collected from provincial veterinary of Hamadan. The relationship between the animals vaccination coverage with the incidence of human brucellosis was assessed with the SPSS software. Pearson correlation coefficient was used to evaluate the correlation between animal vaccination and human brucellosis.

Results: According to provincial veterinary of Hamadan reports, animal vaccination coverage (percentage) from 2002 to 2008 was between 17.5% in 2002 and increased to 60% in 2008 in young sheep and goats, and vaccination coverage against brucellosis in young cattles was 5.6% in 2002 and increased to 38% in 2008. According to Hamadan health deputy human brucellosis incidence rate was 86 per 100000 persons in 2002 and reduced to 44.7 per 100000 persons in 2008. Statistical analysis showed that Pearson correlation coefficient of cattle vaccination and human brucellosis(r = -0.78), sheep's vaccination and human incidence rate (r = - 0.38 ) are negative but incomplete.

Conclusion: Vaccination of young animals was effective in reducing the incidence rate of human brucellosis. Our findings emphasize the importance of the combination of health education and animal vaccination programs for controlling such zoonosis diseases and highlight the need for cooperation between public health officials and veterinary officers