The Mansfield/Ontario/Richland County Health Department in Ohio is part of a national effort to increase immunization rates for children under age of two. Children should have more than 80 percent of their vaccinations within the first two years of life, and health officials say that vaccinations are the most important method to protect children against disease. Although most vaccine-preventable diseases have been significantly reduced since the advent of vaccines, over 900,000 U.S. children are still not completely immunized.