 The purpose of this study is to evaluate the safety and effectiveness of a vaccine given to women ages 18-45 to prevent cytomegalovirus CMV, which they may catch from their children who attend daycare centers. Cytomegalovirus does not usually cause serious illness in adults and children. However, CMV can be a cause of deafness and mental retardation in a child born from a mother who has the infection during pregnancy. Women in the study will be given either cytomegalovirus or Hepatitis A vaccine. A blood sample will be taken before the vaccination is given. After vaccination, urine, saliva, and blood will be collected every 1-6 months for up to 3 years. Information regarding any reaction to the vaccination will be collected. All family members will be asked to provide urine and saliva to test for CMV every few months for up to 3 years. All children born to women who have been vaccinated will be tested for CMV infection. 180 women who are not infected with CMV will be vaccinated. 