Vaccination of school age children and medical workers for preventable diseases should be mandatory to increase herd immunity for those unable to be immunized due to medical reasons.
Vaccination is safe and one of the greatest health developments of the 20th century. Rubella, diphtheria, smallpox, polio, and whooping cough, are now prevented by vaccination and millions of children’s lives are saved and adverse reactions to vaccines are extremely rare.
Center for Disease Control:
http://www.cdc.gov/globalhealth/immunization/research.htm
World Health Organization:
http://www.who.int/topics/immunization/en/