Of the 16 immunizations the CDC recommends for children and teens, all 50 states (plus the District of Columbia) mandate diphtheria, tetanus, pertussis (whooping cough), polio, measles, rubella and chickenpox. In addition, every state except Iowa mandates immunization against mumps. (The diphtheria, tetanus and pertussis vaccines usually are given as a single combined shot, as are the measles, mumps and rubella vaccines.) Except for the chickenpox vaccine, which became available in the United States in 1995, all those vaccines have been around for 50 years or more.