SPRINGFIELD –The Illinois Department of Public Health (IDPH) is reporting the highest number of pertussis (whooping cough) cases in Illinois since 1950. Preliminary numbers show 2,026 cases of pertussis in Illinois residents in 2012. During National Infant Immunization Week, April 20-27, 2013, the Department urges parents to make sure their children have received all 14 recommended vaccinations, which includes pertussis, before age two.