Illinois health officials are calling attention to an increase in whooping cough cases this year as they remind parents about required immunizations for children. Approximately 1,200 cases of whooping cough have been reported in the state so far this year. That's compared to 468 cases reported as of last August. Sixth- and ninth-grade students are now required to show proof of receiving the Tdap vaccine for tetanus, diphtheria and pertussis, better known as whooping cough. The Illinois Department of Public Health said students who don’t show proof of vaccination must make an appointment to get it or have an approved medical or religious exemption on file.