Several were the leading cause of death among infants and children in the days before immunizations. Keeping children healthy and preventing these serious illnesses and their complications are only two of the reasons for immunization. From a practical standpoint, children may not be allowed to enter day care or school or participate in summer camp or sports activities if they haven't been immunized. Most all of the immunizations are now required by law in most states. Parents must make a commitment to take their child to the doctor or clinic for regular visits, and it means keeping good records on their own, especially if they don't get all the immunizations at the same place.
All medications can have some unwanted effects.
This is true of vaccines as well. For a very, very few children, however, more serious side effects are possible. For most children, the risk of contracting the disease is far greater than the risk of suffering a serious side effect from the immunization. If your child is old enough, explain that immunizations prevent some very bad diseases. Children feel less of a sting when they do so.